Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues:
Rental revenue	$ 117,113	$ 114,908
Tenant expense reimbursement	15,974	18,120
Observatory revenue	20,940	21,181
Third-party management and other fees	351	545
Other revenue and fees	10,576	2,320
Total revenues	164,954	157,074
Operating expenses:
Property operating expenses	42,210	39,104
Ground rent expenses	2,331	2,333
General and administrative expenses	11,088	10,918
Observatory expenses	7,255	7,755
Real estate taxes	24,558	23,525
Acquisition expenses	0	98
Depreciation and amortization	40,846	39,227
Total operating expenses	128,288	122,960
Total operating income	36,666	34,114
Other expense:
Interest expense	(17,742)	(17,951)
Loss from derivative financial instruments	(247)	0
Income before income taxes	18,677	16,163
Income tax benefit	468	542
Net income	19,145	16,705
Private perpetual preferred unit distributions	(234)	(234)
Net income attributable to non-controlling interests	(8,926)	(9,043)
Net income attributable to common stockholders	$ 9,985	$ 7,428
Total weighted average shares:
Basic (in shares)	156,493	120,778
Diluted (in shares)	297,962	266,641
Earnings per share attributable to common stockholders:
Basic (in USD per share)	$ 0.06	$ 0.06
Diluted (in USD per share)	0.06	0.06
Dividends per share (in USD per share)	$ 0.105	$ 0.085