Schedule III Real Estate Assets and Accumulated Depreciation and Amortization - Schedule III (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Real Estate Properties [Line Items]
Encumbrances	$ 1,018,015
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	584,291
Building and Improvements	4,633,517
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	352,352
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	584,291
Building and Improvements	4,985,869
Total	5,570,160	$ 4,310,302	$ 4,278,433	$ 3,073,364
Accumulated Depreciation and Amortization	993,323	$ 817,773	$ 668,104	$ 538,412
Loan valuation discount	1,000
Aggregate cost of real estate owned for income tax purposes	5,000,000
Operating Properties | Plainfield
Real Estate Properties [Line Items]
Encumbrances	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,709
Building and Improvements	22,209
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	7,344
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,709
Building and Improvements	29,553
Total	33,262
Accumulated Depreciation and Amortization	$ 16,703
Operating Properties | Plainfield | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Plainfield | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Renfro
Real Estate Properties [Line Items]
Encumbrances	$ 12,247
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,400
Building and Improvements	18,182
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,012
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,400
Building and Improvements	20,194
Total	21,594
Accumulated Depreciation and Amortization	$ 9,987
Operating Properties | Renfro | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Renfro | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Emporia Partners
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	274
Building and Improvements	7,567
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	962
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	274
Building and Improvements	8,529
Total	8,803
Accumulated Depreciation and Amortization	$ 3,366
Operating Properties | Emporia Partners | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Emporia Partners | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | AT&T
Real Estate Properties [Line Items]
Encumbrances	$ 23,585
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,770
Building and Improvements	32,420
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	718
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,770
Building and Improvements	33,138
Total	39,908
Accumulated Depreciation and Amortization	$ 11,934
Operating Properties | AT&T | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | AT&T | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Westinghouse
Real Estate Properties [Line Items]
Encumbrances	$ 19,957
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,650
Building and Improvements	26,745
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	54
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,650
Building and Improvements	26,799
Total	29,449
Accumulated Depreciation and Amortization	$ 10,104
Operating Properties | Westinghouse | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Westinghouse | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | TransDigm
Real Estate Properties [Line Items]
Encumbrances	$ 4,173
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,773
Building and Improvements	9,030
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	411
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,773
Building and Improvements	9,441
Total	13,214
Accumulated Depreciation and Amortization	$ 3,272
Operating Properties | TransDigm | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | TransDigm | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Atrium II
Real Estate Properties [Line Items]
Encumbrances	$ 8,618
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,600
Building and Improvements	13,500
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	10,643
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,600
Building and Improvements	24,143
Total	26,743
Accumulated Depreciation and Amortization	$ 7,770
Operating Properties | Atrium II | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Atrium II | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Zeller Plastik
Real Estate Properties [Line Items]
Encumbrances	$ 8,164
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,674
Building and Improvements	13,229
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	651
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,674
Building and Improvements	13,880
Total	16,554
Accumulated Depreciation and Amortization	$ 4,767
Operating Properties | Zeller Plastik | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Zeller Plastik | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Northrop Grumman
Real Estate Properties [Line Items]
Encumbrances	$ 9,945
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,300
Building and Improvements	16,188
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	39
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,300
Building and Improvements	16,227
Total	17,527
Accumulated Depreciation and Amortization	$ 7,232
Operating Properties | Northrop Grumman | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Northrop Grumman | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Health Net
Real Estate Properties [Line Items]
Encumbrances	$ 12,246
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,182
Building and Improvements	18,072
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	324
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,182
Building and Improvements	18,396
Total	22,578
Accumulated Depreciation and Amortization	$ 9,969
Operating Properties | Health Net | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Health Net | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Comcast
Real Estate Properties [Line Items]
Encumbrances	$ 14,105
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,146
Building and Improvements	22,826
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,927
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,146
Building and Improvements	24,753
Total	27,899
Accumulated Depreciation and Amortization	$ 12,378
Operating Properties | Comcast | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Comcast | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | 500 Rivertech
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,000
Building and Improvements	9,000
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	6,784
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,000
Building and Improvements	15,784
Total	18,784
Accumulated Depreciation and Amortization	$ 6,142
Operating Properties | 500 Rivertech | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | 500 Rivertech | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Schlumberger
Real Estate Properties [Line Items]
Encumbrances	$ 27,681
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,800
Building and Improvements	47,752
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,285
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,800
Building and Improvements	49,037
Total	51,837
Accumulated Depreciation and Amortization	$ 15,455
Operating Properties | Schlumberger | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Schlumberger | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | UTC
Real Estate Properties [Line Items]
Encumbrances	$ 21,879
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,330
Building and Improvements	37,858
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,330
Building and Improvements	37,858
Total	39,188
Accumulated Depreciation and Amortization	$ 12,989
Operating Properties | UTC | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | UTC | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Avnet
Real Estate Properties [Line Items]
Encumbrances	$ 18,288
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,860
Building and Improvements	31,481
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	47
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,860
Building and Improvements	31,528
Total	33,388
Accumulated Depreciation and Amortization	$ 8,792
Operating Properties | Avnet | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Avnet | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Cigna
Real Estate Properties [Line Items]
Encumbrances	$ 39,000
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	8,600
Building and Improvements	48,102
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	133
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	8,600
Building and Improvements	48,235
Total	56,835
Accumulated Depreciation and Amortization	$ 16,633
Operating Properties | Cigna | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Cigna | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Amazon - Arlington Heights
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	7,697
Building and Improvements	21,843
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	5,879
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	7,697
Building and Improvements	27,722
Total	35,419
Accumulated Depreciation and Amortization	$ 8,208
Operating Properties | Amazon - Arlington Heights | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Amazon - Arlington Heights | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Verizon
Real Estate Properties [Line Items]
Encumbrances	$ 24,089
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,300
Building and Improvements	36,768
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	14,063
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,300
Building and Improvements	50,831
Total	56,131
Accumulated Depreciation and Amortization	$ 19,501
Operating Properties | Verizon | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Verizon | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Fox Head
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,672
Building and Improvements	23,230
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,672
Building and Improvements	23,230
Total	26,902
Accumulated Depreciation and Amortization	$ 6,740
Operating Properties | Fox Head | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Fox Head | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | 2500 Windy Ridge
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,000
Building and Improvements	50,227
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	18,247
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,000
Building and Improvements	68,474
Total	73,474
Accumulated Depreciation and Amortization	$ 19,957
Operating Properties | 2500 Windy Ridge | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | 2500 Windy Ridge | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | General Electric
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,050
Building and Improvements	51,396
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	132
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,050
Building and Improvements	51,528
Total	56,578
Accumulated Depreciation and Amortization	$ 14,528
Operating Properties | General Electric | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | General Electric | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Atlanta Wildwood
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,241
Building and Improvements	23,414
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	9,051
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,241
Building and Improvements	32,465
Total	36,706
Accumulated Depreciation and Amortization	$ 11,175
Operating Properties | Atlanta Wildwood | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Atlanta Wildwood | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Community Insurance
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,177
Building and Improvements	22,323
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	3,725
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,177
Building and Improvements	26,048
Total	27,225
Accumulated Depreciation and Amortization	$ 7,124
Operating Properties | Community Insurance | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Community Insurance | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Anthem
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	850
Building and Improvements	8,892
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	175
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	850
Building and Improvements	9,067
Total	9,917
Accumulated Depreciation and Amortization	$ 3,224
Operating Properties | Anthem | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Anthem | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | JPMorgan Chase
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,500
Building and Improvements	39,000
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,335
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,500
Building and Improvements	40,335
Total	45,835
Accumulated Depreciation and Amortization	$ 13,540
Operating Properties | JPMorgan Chase | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | JPMorgan Chase | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Sterling Commerce Center
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,750
Building and Improvements	32,769
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	5,460
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,750
Building and Improvements	38,229
Total	42,979
Accumulated Depreciation and Amortization	$ 14,032
Operating Properties | Sterling Commerce Center | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Sterling Commerce Center | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Aetna (Arlington)
Real Estate Properties [Line Items]
Encumbrances	$ 36,199
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,000
Building and Improvements	12,330
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,793
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,000
Building and Improvements	14,123
Total	17,123
Accumulated Depreciation and Amortization	$ 5,277
Operating Properties | Aetna (Arlington) | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Aetna (Arlington) | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | CHRISTUS Health
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,950
Building and Improvements	46,922
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	377
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,950
Building and Improvements	47,299
Total	49,249
Accumulated Depreciation and Amortization	$ 18,025
Operating Properties | CHRISTUS Health | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | CHRISTUS Health | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Roush Industries
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	875
Building and Improvements	11,375
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,615
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	875
Building and Improvements	13,990
Total	14,865
Accumulated Depreciation and Amortization	$ 4,283
Operating Properties | Roush Industries | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Roush Industries | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Parkland Center
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,100
Building and Improvements	26,348
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	11,063
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,100
Building and Improvements	37,411
Total	40,511
Accumulated Depreciation and Amortization	$ 19,098
Operating Properties | Parkland Center | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Parkland Center | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | 1200 Morris
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,925
Building and Improvements	18,935
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,798
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,925
Building and Improvements	21,733
Total	24,658
Accumulated Depreciation and Amortization	$ 8,759
Operating Properties | 1200 Morris | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | 1200 Morris | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | United HealthCare
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,920
Building and Improvements	23,510
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	9,243
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,920
Building and Improvements	32,753
Total	35,673
Accumulated Depreciation and Amortization	$ 10,384
Operating Properties | United HealthCare | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | United HealthCare | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Intermec (Northpointe Corporate Center II)
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,109
Building and Improvements	6,066
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	4,576
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,109
Building and Improvements	10,642
Total	11,751
Accumulated Depreciation and Amortization	$ 5,806
Operating Properties | Intermec (Northpointe Corporate Center II) | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Intermec (Northpointe Corporate Center II) | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Comcast (Northpointe Corporate Center I)
Real Estate Properties [Line Items]
Encumbrances	$ 39,650
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,292
Building and Improvements	16,930
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,324
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,292
Building and Improvements	19,254
Total	21,546
Accumulated Depreciation and Amortization	$ 6,141
Operating Properties | Comcast (Northpointe Corporate Center I) | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Comcast (Northpointe Corporate Center I) | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Farmers
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,750
Building and Improvements	17,106
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	816
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,750
Building and Improvements	17,922
Total	20,672
Accumulated Depreciation and Amortization	$ 7,430
Operating Properties | Farmers | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Farmers | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Digital Globe
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	8,600
Building and Improvements	83,400
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	8,600
Building and Improvements	83,400
Total	92,000
Accumulated Depreciation and Amortization	$ 25,498
Operating Properties | Digital Globe | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Digital Globe | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Waste Management
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	0
Building and Improvements	16,515
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	82
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	0
Building and Improvements	16,597
Total	16,597
Accumulated Depreciation and Amortization	$ 7,126
Operating Properties | Waste Management | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Waste Management | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Wyndham Worldwide
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,200
Building and Improvements	91,153
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,494
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,200
Building and Improvements	93,647
Total	99,847
Accumulated Depreciation and Amortization	$ 22,527
Operating Properties | Wyndham Worldwide | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Wyndham Worldwide | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | ACE Hardware Corporation HQ
Real Estate Properties [Line Items]
Encumbrances	$ 22,750
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,900
Building and Improvements	33,945
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,900
Building and Improvements	33,945
Total	40,845
Accumulated Depreciation and Amortization	$ 9,992
Operating Properties | ACE Hardware Corporation HQ | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | ACE Hardware Corporation HQ | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Equifax
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,850
Building and Improvements	12,709
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	578
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,850
Building and Improvements	13,287
Total	15,137
Accumulated Depreciation and Amortization	$ 5,355
Operating Properties | Equifax | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Equifax | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | American Express
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	15,000
Building and Improvements	45,893
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	18,372
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	15,000
Building and Improvements	64,265
Total	79,265
Accumulated Depreciation and Amortization	$ 19,934
Operating Properties | American Express | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | American Express | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Circle Star
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	22,789
Building and Improvements	68,950
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	5,272
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	22,789
Building and Improvements	74,222
Total	97,011
Accumulated Depreciation and Amortization	$ 26,884
Operating Properties | Circle Star | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Circle Star | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Vanguard
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,230
Building and Improvements	31,062
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	838
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,230
Building and Improvements	31,900
Total	34,130
Accumulated Depreciation and Amortization	$ 10,067
Operating Properties | Vanguard | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Vanguard | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Parallon
Real Estate Properties [Line Items]
Encumbrances	$ 6,803
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,000
Building and Improvements	16,772
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,000
Building and Improvements	16,772
Total	17,772
Accumulated Depreciation and Amortization	$ 5,206
Operating Properties | Parallon | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Parallon | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | TW Telecom
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	10,554
Building and Improvements	35,817
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,663
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	10,554
Building and Improvements	37,480
Total	48,034
Accumulated Depreciation and Amortization	$ 12,727
Operating Properties | TW Telecom | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | TW Telecom | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Equifax II
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,200
Building and Improvements	12,755
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	234
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,200
Building and Improvements	12,989
Total	15,189
Accumulated Depreciation and Amortization	$ 4,559
Operating Properties | Equifax II | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Equifax II | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Mason I
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,777
Building and Improvements	18,489
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	746
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,777
Building and Improvements	19,235
Total	24,012
Accumulated Depreciation and Amortization	$ 3,502
Operating Properties | Mason I | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Mason I | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Wells Fargo (Charlotte)
Real Estate Properties [Line Items]
Encumbrances	$ 26,975
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,150
Building and Improvements	40,806
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	46
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,150
Building and Improvements	40,852
Total	43,002
Accumulated Depreciation and Amortization	$ 11,353
Operating Properties | Wells Fargo (Charlotte) | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Wells Fargo (Charlotte) | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | GE Aviation
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,400
Building and Improvements	61,681
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,400
Building and Improvements	61,681
Total	66,081
Accumulated Depreciation and Amortization	$ 17,230
Operating Properties | GE Aviation | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | GE Aviation | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Westgate III
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,209
Building and Improvements	75,937
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,209
Building and Improvements	75,937
Total	79,146
Accumulated Depreciation and Amortization	$ 18,948
Operating Properties | Westgate III | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Westgate III | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Franklin Center
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,989
Building and Improvements	46,875
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,441
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,989
Building and Improvements	48,316
Total	55,305
Accumulated Depreciation and Amortization	$ 11,157
Operating Properties | Franklin Center | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Franklin Center | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | 4650 Lakehurst Court
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,943
Building and Improvements	22,651
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	808
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,943
Building and Improvements	23,459
Total	26,402
Accumulated Depreciation and Amortization	$ 9,831
Operating Properties | 4650 Lakehurst Court | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | 4650 Lakehurst Court | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Miramar
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,488
Building and Improvements	19,979
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,233
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,488
Building and Improvements	22,212
Total	26,700
Accumulated Depreciation and Amortization	$ 6,020
Operating Properties | Miramar | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Miramar | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Royal Ridge V
Real Estate Properties [Line Items]
Encumbrances	$ 21,385
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,842
Building and Improvements	22,052
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	3,667
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,842
Building and Improvements	25,719
Total	27,561
Accumulated Depreciation and Amortization	$ 6,639
Operating Properties | Royal Ridge V | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Royal Ridge V | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Duke Bridges
Real Estate Properties [Line Items]
Encumbrances	$ 27,475
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	8,239
Building and Improvements	51,395
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	8,291
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	8,239
Building and Improvements	59,686
Total	67,925
Accumulated Depreciation and Amortization	$ 13,122
Operating Properties | Duke Bridges | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Duke Bridges | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Houston Westway II
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,961
Building and Improvements	78,668
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,612
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,961
Building and Improvements	80,280
Total	84,241
Accumulated Depreciation and Amortization	$ 22,120
Operating Properties | Houston Westway II | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Houston Westway II | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Atlanta Perimeter
Real Estate Properties [Line Items]
Encumbrances	$ 69,461
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	8,382
Building and Improvements	96,718
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	900
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	8,382
Building and Improvements	97,618
Total	106,000
Accumulated Depreciation and Amortization	$ 36,514
Operating Properties | Atlanta Perimeter | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Atlanta Perimeter | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | South Lake at Dulles
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	9,666
Building and Improvements	74,098
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	26,512
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	9,666
Building and Improvements	100,610
Total	110,276
Accumulated Depreciation and Amortization	$ 22,333
Operating Properties | South Lake at Dulles | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | South Lake at Dulles | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Four Parkway
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,339
Building and Improvements	37,298
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	6,584
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,339
Building and Improvements	43,882
Total	48,221
Accumulated Depreciation and Amortization	$ 13,197
Operating Properties | Four Parkway | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Four Parkway | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Highway 94
Real Estate Properties [Line Items]
Encumbrances	$ 13,732
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,637
Building and Improvements	25,280
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,637
Building and Improvements	25,280
Total	30,917
Accumulated Depreciation and Amortization	$ 7,528
Operating Properties | Highway 94 | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Highway 94 | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Heritage III
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,955
Building and Improvements	15,540
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	6,719
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,955
Building and Improvements	22,259
Total	24,214
Accumulated Depreciation and Amortization	$ 4,629
Operating Properties | Heritage III | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Heritage III | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Heritage IV
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,330
Building and Improvements	26,376
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	4,909
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,330
Building and Improvements	31,285
Total	33,615
Accumulated Depreciation and Amortization	$ 7,207
Operating Properties | Heritage IV | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Heritage IV | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Samsonite
Real Estate Properties [Line Items]
Encumbrances	$ 19,114
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,040
Building and Improvements	42,490
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	11
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,040
Building and Improvements	42,501
Total	47,541
Accumulated Depreciation and Amortization	$ 9,234
Operating Properties | Samsonite | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Samsonite | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Restoration Hardware
Real Estate Properties [Line Items]
Encumbrances	$ 78,000
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	15,463
Building and Improvements	36,613
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	37,693
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	15,463
Building and Improvements	74,306
Total	89,769
Accumulated Depreciation and Amortization	$ 21,857
Operating Properties | Restoration Hardware | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Restoration Hardware | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | HealthSpring
Real Estate Properties [Line Items]
Encumbrances	$ 19,669
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	8,126
Building and Improvements	31,447
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	43
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	8,126
Building and Improvements	31,490
Total	39,616
Accumulated Depreciation and Amortization	$ 8,346
Operating Properties | HealthSpring | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | HealthSpring | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | LPL
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,612
Building and Improvements	86,352
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,612
Building and Improvements	86,352
Total	90,964
Accumulated Depreciation and Amortization	$ 10,351
Operating Properties | LPL | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | LPL | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | LPL
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,274
Building and Improvements	41,509
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,273
Building and Improvements	41,509
Total	42,782
Accumulated Depreciation and Amortization	$ 4,976
Operating Properties | LPL | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | LPL | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Quaker
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,433
Building and Improvements	55,341
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,433
Building and Improvements	55,341
Total	60,774
Accumulated Depreciation and Amortization	$ 6,455
Operating Properties | Quaker | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Quaker | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | McKesson
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	312
Building and Improvements	69,760
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	312
Building and Improvements	69,760
Total	70,072
Accumulated Depreciation and Amortization	$ 13,496
Operating Properties | McKesson | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | McKesson | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Shaw Industries
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,465
Building and Improvements	57,116
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,465
Building and Improvements	57,116
Total	62,581
Accumulated Depreciation and Amortization	$ 6,512
Operating Properties | Shaw Industries | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Shaw Industries | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | GEAR Entities
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,584
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,584
Building and Improvements	0
Total	1,584
Accumulated Depreciation and Amortization	0
Operating Properties | Owens Corning
Real Estate Properties [Line Items]
Encumbrances	3,239
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	867
Building and Improvements	4,418
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,101
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	867
Building and Improvements	5,519
Total	6,386
Accumulated Depreciation and Amortization	$ 825
Operating Properties | Owens Corning | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Owens Corning | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Westgate II
Real Estate Properties [Line Items]
Encumbrances	$ 33,563
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	7,716
Building and Improvements	48,422
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	870
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	7,716
Building and Improvements	49,292
Total	57,008
Accumulated Depreciation and Amortization	$ 8,062
Operating Properties | Westgate II | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Westgate II | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Administrative Office of Pennsylvania Courts
Real Estate Properties [Line Items]
Encumbrances	$ 5,957
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,246
Building and Improvements	9,626
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	781
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,246
Building and Improvements	10,407
Total	11,653
Accumulated Depreciation and Amortization	$ 1,631
Operating Properties | Administrative Office of Pennsylvania Courts | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Administrative Office of Pennsylvania Courts | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | American Express Center
Real Estate Properties [Line Items]
Encumbrances	$ 53,878
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	10,595
Building and Improvements	82,098
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	3,109
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	10,595
Building and Improvements	85,207
Total	95,802
Accumulated Depreciation and Amortization	$ 15,274
Operating Properties | American Express Center | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | American Express Center | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | MGM Corporate Center
Real Estate Properties [Line Items]
Encumbrances	$ 17,842
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,546
Building and Improvements	25,825
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,827
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,546
Building and Improvements	27,652
Total	32,198
Accumulated Depreciation and Amortization	$ 4,531
Operating Properties | MGM Corporate Center | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | MGM Corporate Center | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | American Showa
Real Estate Properties [Line Items]
Encumbrances	$ 10,128
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,214
Building and Improvements	16,538
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,484
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,214
Building and Improvements	19,022
Total	20,236
Accumulated Depreciation and Amortization	$ 2,537
Operating Properties | American Showa | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | American Showa | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Huntington Ingalls
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,213
Building and Improvements	29,219
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,674
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,213
Building and Improvements	31,893
Total	38,106
Accumulated Depreciation and Amortization	$ 4,332
Operating Properties | Huntington Ingalls | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Huntington Ingalls | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Wyndham
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	9,677
Building and Improvements	71,316
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,742
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	9,677
Building and Improvements	73,058
Total	82,735
Accumulated Depreciation and Amortization	$ 9,070
Operating Properties | Wyndham | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Wyndham | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Exel
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	978
Building and Improvements	14,137
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,568
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	978
Building and Improvements	16,705
Total	17,683
Accumulated Depreciation and Amortization	$ 3,100
Operating Properties | Exel | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Exel | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Rapiscan Systems
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,006
Building and Improvements	10,270
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	484
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,006
Building and Improvements	10,754
Total	12,760
Accumulated Depreciation and Amortization	$ 1,618
Operating Properties | Rapiscan Systems | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Rapiscan Systems | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Aetna
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,332
Building and Improvements	18,486
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,598
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,332
Building and Improvements	20,084
Total	22,416
Accumulated Depreciation and Amortization	$ 3,199
Operating Properties | Aetna | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Aetna | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Atlas Copco
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,156
Building and Improvements	18,297
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,505
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,156
Building and Improvements	19,802
Total	20,958
Accumulated Depreciation and Amortization	$ 2,763
Operating Properties | Atlas Copco | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Atlas Copco | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Toshiba TEC
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,916
Building and Improvements	36,374
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,423
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,916
Building and Improvements	38,797
Total	40,713
Accumulated Depreciation and Amortization	$ 5,186
Operating Properties | Toshiba TEC | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Toshiba TEC | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | NETGEAR
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	22,600
Building and Improvements	28,859
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,700
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	22,600
Building and Improvements	30,559
Total	53,159
Accumulated Depreciation and Amortization	$ 6,071
Operating Properties | NETGEAR | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | NETGEAR | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Nike
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	8,186
Building and Improvements	41,184
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,330
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	8,187
Building and Improvements	43,514
Total	51,701
Accumulated Depreciation and Amortization	$ 7,610
Operating Properties | Nike | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Nike | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Zebra Technologies
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,927
Building and Improvements	58,688
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,255
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,927
Building and Improvements	59,943
Total	65,870
Accumulated Depreciation and Amortization	$ 9,853
Operating Properties | Zebra Technologies | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Zebra Technologies | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | WABCO
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,226
Building and Improvements	13,902
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,038
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,226
Building and Improvements	14,940
Total	16,166
Accumulated Depreciation and Amortization	$ 1,394
Operating Properties | WABCO | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | WABCO | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | IGT
Real Estate Properties [Line Items]
Encumbrances	$ 45,300
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,673
Building and Improvements	67,610
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,021
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,673
Building and Improvements	69,631
Total	75,304
Accumulated Depreciation and Amortization	$ 7,191
Operating Properties | IGT | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | IGT | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | 3M
Real Estate Properties [Line Items]
Encumbrances	$ 43,600
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,802
Building and Improvements	75,758
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	6,391
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,802
Building and Improvements	82,149
Total	87,951
Accumulated Depreciation and Amortization	$ 7,010
Operating Properties | 3M | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | 3M | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Amazon - Etna
Real Estate Properties [Line Items]
Encumbrances	$ 61,500
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,773
Building and Improvements	95,475
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	11,546
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,773
Building and Improvements	107,021
Total	111,794
Accumulated Depreciation and Amortization	$ 10,861
Operating Properties | Amazon - Etna | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Amazon - Etna | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Zoetis
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,718
Building and Improvements	44,082
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	735
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,718
Building and Improvements	44,817
Total	48,535
Accumulated Depreciation and Amortization	$ 5,221
Operating Properties | Zoetis | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Zoetis | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Southern Company
Real Estate Properties [Line Items]
Encumbrances	$ 99,600
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	7,794
Building and Improvements	157,724
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,457
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	7,794
Building and Improvements	159,181
Total	166,975
Accumulated Depreciation and Amortization	$ 12,166
Operating Properties | Southern Company | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Southern Company | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Allstate
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,109
Building and Improvements	13,096
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	553
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,109
Building and Improvements	13,649
Total	16,758
Accumulated Depreciation and Amortization	$ 2,164
Operating Properties | Allstate | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Allstate | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | MISO
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,725
Building and Improvements	25,848
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	971
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,725
Building and Improvements	26,819
Total	30,544
Accumulated Depreciation and Amortization	$ 3,313
Operating Properties | MISO | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | MISO | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | McKesson II
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	0
Building and Improvements	36,959
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	4,681
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	0
Building and Improvements	41,640
Total	41,640
Accumulated Depreciation and Amortization	$ 5,021
Operating Properties | McKesson II | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | McKesson II | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Pepsi Bottling Ventures
Real Estate Properties [Line Items]
Encumbrances	$ 18,218
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,407
Building and Improvements	31,783
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	954
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,407
Building and Improvements	32,737
Total	36,144
Accumulated Depreciation and Amortization	$ 2,186
Operating Properties | Pepsi Bottling Ventures | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Pepsi Bottling Ventures | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | State of Alabama
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	8,126
Building and Improvements	39,248
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	458
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	8,126
Building and Improvements	39,706
Total	47,832
Accumulated Depreciation and Amortization	$ 2,041
Operating Properties | State of Alabama | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | State of Alabama | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | CAS, Inc.
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,007
Building and Improvements	23,327
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,494
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,007
Building and Improvements	24,821
Total	29,828
Accumulated Depreciation and Amortization	$ 1,741
Operating Properties | CAS, Inc. | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | CAS, Inc. | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Freeport McMoRan
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,264
Building and Improvements	120,604
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	82
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,264
Building and Improvements	120,686
Total	124,950
Accumulated Depreciation and Amortization	$ 5,192
Operating Properties | Freeport McMoRan | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Freeport McMoRan | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Avnet HQ
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,394
Building and Improvements	31,021
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,862
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,394
Building and Improvements	32,883
Total	38,277
Accumulated Depreciation and Amortization	$ 2,089
Operating Properties | Avnet HQ | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Avnet HQ | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Terraces at Copley Point
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	23,897
Building and Improvements	87,430
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,250
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	23,897
Building and Improvements	88,680
Total	112,577
Accumulated Depreciation and Amortization	$ 4,696
Operating Properties | Terraces at Copley Point | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Terraces at Copley Point | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | County of Santa Clara
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	16,068
Building and Improvements	18,359
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,126
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	16,068
Building and Improvements	19,485
Total	35,553
Accumulated Depreciation and Amortization	$ 1,274
Operating Properties | County of Santa Clara | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | County of Santa Clara | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | ProteinSimple
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	12,674
Building and Improvements	48,553
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,417
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	12,674
Building and Improvements	49,970
Total	62,644
Accumulated Depreciation and Amortization	$ 2,184
Operating Properties | ProteinSimple | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | ProteinSimple | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Traveler's Insurance
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,069
Building and Improvements	11,715
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	590
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,069
Building and Improvements	12,305
Total	17,374
Accumulated Depreciation and Amortization	$ 744
Operating Properties | Traveler's Insurance | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Traveler's Insurance | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Anadarko
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,841
Building and Improvements	24,702
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,794
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,841
Building and Improvements	26,496
Total	33,337
Accumulated Depreciation and Amortization	$ 1,057
Operating Properties | Anadarko | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Anadarko | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | DuPont
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,412
Building and Improvements	39,299
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,624
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,412
Building and Improvements	40,923
Total	47,335
Accumulated Depreciation and Amortization	$ 1,917
Operating Properties | DuPont | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | DuPont | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Mercury Systems
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	6,969
Building and Improvements	37,739
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	900
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	6,969
Building and Improvements	38,639
Total	45,608
Accumulated Depreciation and Amortization	$ 1,737
Operating Properties | Mercury Systems | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Mercury Systems | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Draeger Medical Systems
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,985
Building and Improvements	30,143
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,114
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,985
Building and Improvements	31,257
Total	36,242
Accumulated Depreciation and Amortization	$ 1,515
Operating Properties | Draeger Medical Systems | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Draeger Medical Systems | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Keurig - Phase I
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	5,111
Building and Improvements	48,464
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	812
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	5,111
Building and Improvements	49,276
Total	54,387
Accumulated Depreciation and Amortization	$ 1,683
Operating Properties | Keurig - Phase I | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Keurig - Phase I | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Keurig - Phase II
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,262
Building and Improvements	169,233
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	628
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,262
Building and Improvements	169,861
Total	173,123
Accumulated Depreciation and Amortization	$ 5,165
Operating Properties | Keurig - Phase II | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Keurig - Phase II | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | JMT
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,873
Building and Improvements	50,619
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,060
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,873
Building and Improvements	51,679
Total	54,552
Accumulated Depreciation and Amortization	$ 1,490
Operating Properties | JMT | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | JMT | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Fidelity Building Services
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,662
Building and Improvements	10,746
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	435
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,662
Building and Improvements	11,181
Total	12,843
Accumulated Depreciation and Amortization	$ 354
Operating Properties | Fidelity Building Services | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Fidelity Building Services | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | United Rentals
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,847
Building and Improvements	30,163
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	726
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,847
Building and Improvements	30,889
Total	33,736
Accumulated Depreciation and Amortization	$ 1,262
Operating Properties | United Rentals | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | United Rentals | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | QORVO
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	2,436
Building and Improvements	18,473
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	645
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	2,436
Building and Improvements	19,118
Total	21,554
Accumulated Depreciation and Amortization	$ 990
Operating Properties | QORVO | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | QORVO | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Ultra Electronics Ocean Systems
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,802
Building and Improvements	9,996
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	523
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,802
Building and Improvements	10,519
Total	12,321
Accumulated Depreciation and Amortization	$ 584
Operating Properties | Ultra Electronics Ocean Systems | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Ultra Electronics Ocean Systems | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Amcor Rigid Plastics
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,962
Building and Improvements	42,377
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,340
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,962
Building and Improvements	43,717
Total	48,679
Accumulated Depreciation and Amortization	$ 2,055
Operating Properties | Amcor Rigid Plastics | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Amcor Rigid Plastics | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Express Scripts
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	4,725
Building and Improvements	18,756
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	2,080
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	4,725
Building and Improvements	20,836
Total	25,561
Accumulated Depreciation and Amortization	$ 1,033
Operating Properties | Express Scripts | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Express Scripts | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | International Paper
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,376
Building and Improvements	69,048
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	8,488
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,376
Building and Improvements	77,536
Total	78,912
Accumulated Depreciation and Amortization	$ 2,468
Operating Properties | International Paper | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | International Paper | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Lennar Homes
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,759
Building and Improvements	17,546
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	715
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,759
Building and Improvements	18,261
Total	20,020
Accumulated Depreciation and Amortization	$ 798
Operating Properties | Lennar Homes | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Lennar Homes | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Dow Chemical
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	685
Building and Improvements	71,064
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,565
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	685
Building and Improvements	72,629
Total	73,314
Accumulated Depreciation and Amortization	$ 2,288
Operating Properties | Dow Chemical | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Dow Chemical | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Tech Data Corp.
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	3,138
Building and Improvements	12,987
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	671
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	3,138
Building and Improvements	13,658
Total	16,796
Accumulated Depreciation and Amortization	$ 648
Operating Properties | Tech Data Corp. | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Tech Data Corp. | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years
Operating Properties | Fresenius Medical Care
Real Estate Properties [Line Items]
Encumbrances	$ 0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost [Abstract]
Land	1,380
Building and Improvements	28,924
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition [Abstract]
Building and Improvements	1,401
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Land	1,380
Building and Improvements	30,325
Total	31,705
Accumulated Depreciation and Amortization	$ 972
Operating Properties | Fresenius Medical Care | Minimum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	5 years
Operating Properties | Fresenius Medical Care | Maximum
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Investment Property, Net [Abstract]
Life on which depreciation in latest income statement is computed	40 years