Condensed Consolidated Statements of Stockholders' Equity - 9 months ended Sep. 30, 2016 - USD ($) $ in Thousands	Total	Class A Common Stock	Class B Common Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Total Stockholders' Equity	Non-controlling Interests	Private Perpetual Preferred Units
Beginning balance (in shares) at Dec. 31, 2015		118,903,312	1,120,067	118,903,000	1,120,000
Beginning balance at Dec. 31, 2015	$ 1,372,686			$ 1,189	$ 11	$ 469,152	$ (883)	$ 55,260	$ 524,729	$ 839,953	$ 8,004
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A shares, net of costs (in shares)				29,611,000
Issuance of Class A shares, net of costs	611,278			$ 296		610,982			611,278
Conversion of operating partnership units and Class B shares to Class A shares (in shares)				5,268,000	(22,000)
Conversion of operating partnership units and Class B shares to Class A shares	0			$ 53	$ 0	20,217	(329)		19,941	(19,941)
Equity compensation:
LTIP units	6,899									6,899
Restricted stock, net of forfeitures (in shares)				46,000
Restricted stock, net of forfeitures	355					355			355
Dividends and distributions	(83,316)							(39,491)	(39,491)	(43,123)	(702)
Net income	74,242							34,490	34,490	39,050	702
Unrealized loss on valuation of interest rate swap agreements	(29,305)						(13,744)		(13,744)	(15,561)
Ending balance (in shares) at Sep. 30, 2016		153,828,060	1,097,584	153,828,000	1,098,000
Ending balance at Sep. 30, 2016	$ 1,952,839			$ 1,538	$ 11	$ 1,100,706	$ (14,956)	$ 50,259	$ 1,137,558	$ 807,277	$ 8,004