Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues:
Rental revenue	$ 120,844	$ 112,613	$ 237,957	$ 227,521
Tenant expense reimbursement	17,569	19,054	33,543	37,174
Observatory revenue	33,966	31,838	54,906	53,019
Third-party management and other fees	392	423	743	968
Other revenue and fees	4,353	1,887	14,929	4,207
Total revenues	177,124	165,815	342,078	322,889
Operating expenses:
Property operating expenses	38,529	37,386	80,739	76,490
Ground rent expenses	2,332	2,330	4,663	4,663
General and administrative expenses	12,579	12,907	23,667	23,825
Observatory expenses	7,176	6,895	14,431	14,650
Real estate taxes	24,542	23,557	49,100	47,082
Acquisition expenses	0	0	0	98
Depreciation and amortization	40,532	38,548	81,378	77,775
Total operating expenses	125,690	121,623	253,978	244,583
Total operating income	51,434	44,192	88,100	78,306
Other expense:
Interest expense	(17,477)	(17,420)	(35,219)	(35,371)
Loss from derivative financial instruments	(42)	0	(289)	0
Income before income taxes	33,915	26,772	52,592	42,935
Income tax expense	(2,556)	(2,132)	(2,088)	(1,590)
Net income	31,359	24,640	50,504	41,345
Private perpetual preferred unit distributions	(234)	(234)	(468)	(468)
Net income attributable to non-controlling interests	(14,541)	(13,317)	(23,467)	(22,360)
Net income attributable to common stockholders	$ 16,584	$ 11,089	$ 26,569	$ 18,517
Total weighted average shares:
Basic (in shares)	157,921	122,502	157,265	121,640
Diluted (in shares)	298,398	266,167	298,180	267,121
Earnings per share attributable to common stockholders:
Basic (in USD per share)	$ 0.10	$ 0.09	$ 0.17	$ 0.15
Diluted (in USD per share)	0.10	0.09	0.17	0.15
Dividends per share (in USD per share)	$ 0.105	$ 0.105	$ 0.21	$ 0.19