Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues:
Rental revenue	$ 110,903	$ 106,152	$ 333,827	$ 288,566
Tenant expense reimbursement	23,096	20,034	59,878	49,491
Observatory revenue	35,702	35,684	84,525	83,374
Construction revenue	0	5,804	1,981	33,730
Third-party management and other fees	618	561	1,658	1,925
Other revenue and fees	5,460	1,206	10,565	7,829
Total revenues	175,779	169,441	492,434	464,915
Operating expenses:
Property operating expenses	41,664	38,291	122,051	109,300
Ground rent expenses	2,331	2,066	6,994	2,964
Marketing, general, and administrative expenses	10,182	10,071	28,395	29,786
Observatory expenses	7,284	7,109	21,681	21,210
Construction expenses	0	6,095	3,222	33,173
Real estate taxes	23,613	21,870	69,543	58,429
Acquisition expenses	193	2,647	193	3,382
Depreciation and amortization	45,169	37,880	126,216	96,632
Total operating expenses	130,436	126,029	378,295	354,876
Total operating income	45,343	43,412	114,139	110,039
Interest expense	(16,680)	(17,674)	(50,298)	(46,640)
Income before income taxes	28,663	25,738	63,841	63,399
Income tax expense	(2,578)	(3,004)	(3,283)	(4,153)
Net income	26,085	22,734	60,558	59,246
Private perpetual preferred unit distributions	(234)	(241)	(702)	(241)
Net income attributable to non-controlling interests	(14,631)	(14,171)	(34,378)	(36,480)
Net income attributable to common stockholders	$ 11,220	$ 8,322	$ 25,478	$ 22,525
Total weighted average shares:
Basic (in shares)	115,900	97,729	112,741	96,226
Diluted (in shares)	265,873	263,041	265,868	250,696
Earnings per share attributable to common stockholders:
Basic (USD per share)	$ 0.10	$ 0.09	$ 0.23	$ 0.23
Diluted (USD pre share)	0.10	0.09	0.22	0.23
Dividends per share (USD per share)	$ 0.085	$ 0.085	$ 0.255	$ 0.255