Segment Reporting - Components of Segment Net Income (Loss) for Each Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenues:
Rental revenue	$ 140,797	$ 137,999	$ 281,028	$ 286,112
Intercompany rental revenue	0	0	0	0
Observatory revenue	8,359	86	10,962	19,630
Lease termination fees	3,339	1,033	4,628	1,244
Third-party management and other fees	327	301	603	647
Other revenue and fees	586	1,611	1,491	3,621
Total revenues	153,408	141,030	298,712	311,254
Operating expenses:
Property operating expenses	28,793	29,750	59,072	71,218
Intercompany rent expense	0	0	0	0
Ground rent expense	2,332	2,332	4,663	4,663
General and administrative expenses	14,089	18,149	27,942	34,100
Observatory expenses	5,268	4,002	9,856	12,156
Real estate taxes	31,354	29,579	62,801	58,833
Impairment charges	0	4,101	0	4,101
Depreciation and amortization	45,088	52,783	89,545	98,876
Total operating expenses	126,924	140,696	253,879	283,947
Total operating income (loss)	26,484	334	44,833	27,307
Other income (expense):
Interest income	164	1,526	286	2,163
Interest expense	(23,422)	(23,928)	(46,976)	(43,546)
Loss on early extinguishment of debt	0	0	(214)	(86)
Income (loss) before income taxes	3,226	(22,068)	(2,071)	(14,162)
Income tax (expense) benefit	1,185	2,450	3,291	2,832
Net income (loss)	4,411	(19,618)	1,220	(11,330)
Segment assets	4,123,472	4,550,395	4,123,472	4,550,395	$ 4,150,695
Expenditures for segment assets	19,975	21,095	43,311	48,904
Intersegment Elimination
Revenues:
Intercompany rental revenue	(6,029)	(4,053)	(10,961)	(15,589)
Total revenues	(6,029)	(4,053)	(10,961)	(15,589)
Operating expenses:
Intercompany rent expense	(6,029)	(4,053)	(10,961)	(15,589)
General and administrative expenses	0	0	0	0
Depreciation and amortization	0	0	0	0
Total operating expenses	(6,029)	(4,053)	(10,961)	(15,589)
Total operating income (loss)	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
Income (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		4,100		4,100
Real Estate | Operating Segments
Revenues:
Rental revenue	140,797	137,999	281,028	286,112
Intercompany rental revenue	6,029	4,053	10,961	15,589
Lease termination fees	3,339	1,033	4,628	1,244
Third-party management and other fees	327	301	603	647
Other revenue and fees	586	1,611	1,491	3,621
Total revenues	151,078	144,997	298,711	307,213
Operating expenses:
Property operating expenses	28,793	29,750	59,072	71,218
Ground rent expense	2,332	2,332	4,663	4,663
General and administrative expenses	14,089	18,149	27,942	34,100
Real estate taxes	31,354	29,579	62,801	58,833
Impairment charges		4,101		4,101
Depreciation and amortization	45,066	52,758	89,485	98,843
Total operating expenses	121,634	136,669	243,963	271,758
Total operating income (loss)	29,444	8,328	54,748	35,455
Other income (expense):
Interest income	163	1,441	283	2,078
Interest expense	(23,422)	(23,928)	(46,976)	(43,546)
Loss on early extinguishment of debt			(214)	(86)
Income (loss) before income taxes	6,185	(14,159)	7,841	(6,099)
Income tax (expense) benefit	(135)	(269)	(418)	(496)
Net income (loss)	6,050	(14,428)	7,423	(6,595)
Segment assets	3,880,853	4,305,105	3,880,853	4,305,105
Expenditures for segment assets	19,975	20,100	43,307	46,672
Observatory | Operating Segments
Revenues:
Intercompany rental revenue	0	0	0	0
Observatory revenue	8,359	86	10,962	19,630
Total revenues	8,359	86	10,962	19,630
Operating expenses:
Intercompany rent expense	6,029	4,053	10,961	15,589
General and administrative expenses	0	0	0	0
Observatory expenses	5,268	4,002	9,856	12,156
Depreciation and amortization	22	25	60	33
Total operating expenses	11,319	8,080	20,877	27,778
Total operating income (loss)	(2,960)	(7,994)	(9,915)	(8,148)
Other income (expense):
Interest income	1	85	3	85
Interest expense	0	0	0	0
Loss on early extinguishment of debt			0
Income (loss) before income taxes	(2,959)	(7,909)	(9,912)	(8,063)
Income tax (expense) benefit	1,320	2,719	3,709	3,328
Net income (loss)	(1,639)	(5,190)	(6,203)	(4,735)
Segment assets	242,619	245,290	242,619	245,290
Expenditures for segment assets	$ 0	$ 995	$ 4	$ 2,232