Segment Reporting - Components of Segment Net Income (Loss) for Each Segment (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenues:
Rental revenue	$ 139,558	$ 139,909		$ 420,586	$ 426,021
Intercompany rental revenue	0	0		0	0
Observatory revenue	12,796	4,419		23,758	24,049
Lease termination fees	11,321	331		15,949	1,575
Third-party management and other fees	314	283		917	930
Other revenue and fees	1,059	1,633		2,550	5,254
Total revenues	165,048	146,575		463,760	457,829
Operating expenses:
Property operating expenses	33,357	33,836		92,429	105,054
Intercompany rent expense	0	0		0	0
Ground rent expense	2,331	2,331		6,994	6,994
General and administrative expenses	14,427	14,517		42,369	48,617
Observatory expenses	6,370	5,931		16,226	18,087
Real estate taxes	29,566	31,196		92,367	90,029
Impairment charges	0	2,103		0	6,204
Depreciation and amortization	65,794	44,733		155,339	143,609
Total operating expenses	151,845	134,647		405,724	418,594
Total operating income	13,203	11,928		58,036	39,235
Other income (expense):
Interest income	211	366		497	2,529
Interest expense	(23,577)	(23,360)		(70,553)	(66,906)
Loss on early extinguishment of debt	0	0		(214)	(86)
IPO litigation expense	0	(1,165)		0	(1,165)
Loss before income taxes	(10,163)	(12,231)		(12,234)	(26,393)
Income tax (expense) benefit	(20)	(38)		3,271	2,794
Net income (loss)	(10,183)	(12,269)		(8,963)	(23,599)
Segment assets	4,112,163	4,010,714		4,112,163	4,010,714	$ 4,150,695
Expenditures for segment assets	21,349	31,347		64,659	80,251
Intersegment Elimination
Revenues:
Intercompany rental revenue	(5,310)	2,233		(16,271)	(13,356)
Total revenues	(5,310)	2,233		(16,271)	(13,356)
Operating expenses:
Intercompany rent expense	(5,310)	2,233		(16,271)	(13,356)
General and administrative expenses	0	0		0	0
Depreciation and amortization	0	0		0	0
Total operating expenses	(5,310)	2,233		(16,271)	(13,356)
Total operating income	0	0		0	0
Other income (expense):
Interest income	0	0		0	0
Interest expense	0	0		0	0
Loss on early extinguishment of debt				0
Loss before income taxes	0	0		0	0
Income tax (expense) benefit	0	0		0	0
Net income (loss)	0	0		0	0
Segment assets	0	0		0	0
Expenditures for segment assets	0	0		0	0
Real Estate
Operating expenses:
Impairment charges		2,100	$ 4,100		6,200
Real Estate | Operating Segments
Revenues:
Rental revenue	139,558	139,909		420,586	426,021
Intercompany rental revenue	5,310	(2,233)		16,271	13,356
Lease termination fees	11,321	331		15,949	1,575
Third-party management and other fees	314	283		917	930
Other revenue and fees	921	1,633		2,412	5,254
Total revenues	157,424	139,923		456,135	447,136
Operating expenses:
Property operating expenses	33,357	33,836		92,429	105,054
Ground rent expense	2,331	2,331		6,994	6,994
General and administrative expenses	14,427	14,517		42,369	48,617
Real estate taxes	29,566	31,196		92,367	90,029
Impairment charges		2,103			6,204
Depreciation and amortization	65,759	44,679		155,244	143,522
Total operating expenses	145,440	128,662		389,403	400,420
Total operating income	11,984	11,261		66,732	46,716
Other income (expense):
Interest income	211	360		494	2,438
Interest expense	(23,577)	(23,360)		(70,553)	(66,906)
Loss on early extinguishment of debt				(214)	(86)
IPO litigation expense		(1,165)			(1,165)
Loss before income taxes	(11,382)	(12,904)		(3,541)	(19,003)
Income tax (expense) benefit	53	(196)		(365)	(692)
Net income (loss)	(11,329)	(13,100)		(3,906)	(19,695)
Segment assets	3,870,142	3,771,476		3,870,142	3,771,476
Expenditures for segment assets	21,349	30,831		64,655	77,503
Observatory | Operating Segments
Revenues:
Intercompany rental revenue	0	0		0	0
Observatory revenue	12,796	4,419		23,758	24,049
Other revenue and fees	138			138
Total revenues	12,934	4,419		23,896	24,049
Operating expenses:
Intercompany rent expense	5,310	(2,233)		16,271	13,356
General and administrative expenses	0	0		0	0
Observatory expenses	6,370	5,931		16,226	18,087
Depreciation and amortization	35	54		95	87
Total operating expenses	11,715	3,752		32,592	31,530
Total operating income	1,219	667		(8,696)	(7,481)
Other income (expense):
Interest income	0	6		3	91
Interest expense	0	0		0	0
Loss on early extinguishment of debt				0
Loss before income taxes	1,219	673		(8,693)	(7,390)
Income tax (expense) benefit	(73)	158		3,636	3,486
Net income (loss)	1,146	831		(5,057)	(3,904)
Segment assets	242,021	239,238		242,021	239,238
Expenditures for segment assets	$ 0	$ 516		$ 4	$ 2,748