Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues:
Rental revenue	$ 115,634	$ 110,903	$ 343,155	$ 333,827
Tenant expense reimbursement	19,176	23,096	56,350	59,878
Observatory revenue	38,093	35,702	91,112	84,525
Construction revenue	0	0	0	1,981
Third-party management and other fees	404	618	1,372	1,658
Other revenue and fees	2,541	5,460	6,748	10,565
Total revenues	175,848	175,779	498,737	492,434
Operating expenses:
Property operating expenses	38,585	41,052	115,075	120,341
Ground rent expenses	2,331	2,331	6,994	6,994
General and administrative expenses	11,798	10,182	35,623	28,395
Observatory expenses	7,250	7,896	21,900	23,391
Construction expenses	0	0	0	3,222
Real estate taxes	24,691	23,613	71,773	69,543
Acquisition expenses	0	193	98	193
Depreciation and amortization	37,607	45,169	115,382	126,216
Total operating expenses	122,262	130,436	366,845	378,295
Total operating income (loss)	53,586	45,343	131,892	114,139
Interest expense	(17,939)	(16,680)	(53,310)	(50,298)
Income (loss) before income taxes	35,647	28,663	78,582	63,841
Income tax expense	(2,750)	(2,578)	(4,340)	(3,283)
Net income (loss)	32,897	26,085	74,242	60,558
Private perpetual preferred unit distributions	(234)	(234)	(702)	(702)
Net income attributable to non-controlling interests	(16,690)	(14,631)	(39,050)	(34,378)
Net income attributable to common stockholders	$ 15,973	$ 11,220	$ 34,490	$ 25,478
Total weighted average shares:
Basic (in shares)	136,831	115,900	126,740	112,741
Diluted (in shares)	280,614	265,873	271,028	265,868
Earnings per share attributable to common stockholders:
Basic (in USD per share)	$ 0.12	$ 0.10	$ 0.27	$ 0.23
Diluted (in USD per share)	0.12	0.10	0.27	0.22
Dividends per share (in USD per share)	$ 0.105	$ 0.085	$ 0.295	$ 0.255