Investment in Unconsolidated and Consolidated Joint Ventures - Condensed Statements of Operations and Balance Sheet Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Information
Assets	$ 238,828	$ 214,155
Borrowings	(131,254)	(121,326)
Equity	97,578	87,568
Investment In	38,240	28,602
Statement of Operations
Revenues		133,739	$ 133,549	$ 121,612
Earnings(Loss)		30,213	5,734	6,371
Equity in Earnings (Loss)		16,575	3,834	4,227
Petro Travel Plaza Holdings, LLC
Balance Sheet Information
Assets	77,835	69,096
Borrowings	(15,287)	(15,283)
Equity	60,061	51,377
Investment In	23,636	18,426
Statement of Operations
Revenues		117,708	119,083	105,507
Earnings(Loss)		14,684	9,672	10,418
Equity in Earnings (Loss)		8,810	5,803	6,251
Five West Parcel, LLC
Balance Sheet Information
Assets	694	15,157
Borrowings	0	(9,173)
Equity	648	5,751
Investment In	140	2,691
Statement of Operations
Revenues		2,648	2,731	2,824
Earnings(Loss)		18,239	778	905
Equity in Earnings (Loss)		9,119	389	452
18-19 West, LLC
Balance Sheet Information
Assets	4,849	4,654
Borrowings	0	0
Equity	4,600	4,654
Investment In	1,730	1,783
Statement of Operations
Revenues		15	13	11
Earnings(Loss)		(107)	(102)	(97)
Equity in Earnings (Loss)		(53)	(51)	(48)
TRCC/Rock Outlet Center, LLC
Balance Sheet Information
Assets	69,459	75,194
Borrowings	(38,909)	(46,826)
Equity	29,688	27,531
Investment In	6,781	5,702
Statement of Operations
Revenues		6,278	6,418	9,615
Earnings(Loss)		(3,843)	(4,645)	(2,347)
Equity in Earnings (Loss)		(1,921)	(2,323)	(1,173)
Non-cash tenant allowance amortization	1,700	1,700	1,700
TRC-MRC 1, LLC
Balance Sheet Information
Assets	28,673	29,692
Borrowings	(24,542)	(25,030)
Equity	3,623	4,018
Investment In	0	0
Statement of Operations
Revenues		3,067	1,323	0
Earnings(Loss)		91	(498)	(3)
Equity in Earnings (Loss)		46	(249)	(2)
TRC-MRC 2, LLC
Balance Sheet Information
Assets	20,026	20,362
Borrowings	(24,455)	(25,014)
Equity	(7,094)	(5,763)
Investment In	0	0
Statement of Operations
Revenues		4,023	3,981	3,655
Earnings(Loss)		1,151	529	(2,505)
Equity in Earnings (Loss)		575	265	(1,253)
Non-cash amortization of purchase accounting adjustments related to in-place leases	200	800
TRC-MRC 3, LLC
Balance Sheet Information
Assets	37,292	0
Borrowings	(28,061)	0
Equity	6,052	0
Investment In	5,953	0
Statement of Operations
Revenues		0	0	0
Earnings(Loss)		(2)	0	0
Equity in Earnings (Loss)		(1)	0	0
Centennial Founders, LLC
Balance Sheet Information
Assets	96,415	93,840
Borrowings	0	0
Equity	$ 96,143	93,188
Statement of Operations
Revenues		469	297	456
Earnings(Loss)		$ (20)	$ (249)	$ (144)