Consolidated Statements of Changes in Equity - 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	Treasury Stock	Retained Earnings/(Dividends in Excess of Earnings)	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests Operating Partnership	Noncontrolling Interests in Consolidated Joint Ventures
Beginning Balance (in shares) at Dec. 31, 2015				55,210,000	44,056,000
Beginning Balance at Dec. 31, 2015	$ 1,491,408			$ 55	$ 44	$ 776,866	$ (5,812)	$ 60,618	$ (3,556)	$ 657,380	$ 5,813
Increase Decrease in Stockholders' Equity
Contributions	250									250
Distributions	(40,562)									(39,805)	(757)
Equity based compensation	17,640					516				17,124
Grants of restricted stock (in shares)				794,000
Grants of restricted stock	0			$ 1		(1)
Purchase of treasury stock (in shares)				(424,000)
Purchase of treasury stock	(4,652)						(4,652)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units (in shares)				(73,000)	(1,000)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units	(786)						(780)			(6)
Forfeitures (in shares)				(48,000)
Forfeitures	0
Dividends declared	(74,393)							(74,393)
Stock dividends (in shares)				5,606,000	4,469,000
Stock dividends	0			$ 6	$ 4	64,090		(64,100)
Exchange of noncontrolling interest for common stock (in shares)				10,521,000	(10,521,000)
Exchange of noncontrolling interest for common stock	0			$ 10	$ (10)	144,629			1,202	(145,831)
Adjustment for deferred taxes/tax receivable agreement as a result of the exchange of Class B shares	(1,590)					(1,590)
Net income (loss)	113,720							66,727		47,131	(138)
Other comprehensive income (loss)	8,519								3,420	5,099
Rebalancing of ownership percentage between Company and Operating Partnership	0					7,797			299	(8,096)
Ending Balance (in shares) at Dec. 31, 2016				71,586,000	38,003,000
Ending Balance at Dec. 31, 2016	1,509,554			$ 72	$ 38	992,307	(11,244)	(11,148)	1,365	533,246	4,918
Increase Decrease in Stockholders' Equity
Distributions	(21,034)									(21,034)
Equity based compensation	7,254					104				7,150
Grants of restricted stock (in shares)				832,000
Grants of restricted stock	0			$ 1		(1)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units (in shares)				(936,000)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units	(13,258)			$ (1)			(13,257)
Dividends declared	(24,700)							(24,700)
Stock dividends (in shares)				814,000	432,000
Stock dividends	0			$ 1	$ 1	17,317		(17,319)
Exchange of noncontrolling interest for common stock (in shares)		6,790,121	(6,790,121)	6,790,000	(6,790,000)
Exchange of noncontrolling interest for common stock	(884)			$ 7	$ (7)	92,397			403	(93,684)
Net income (loss)	19,630							13,470		5,838	322
Other comprehensive income (loss)	4,751								3,117	1,634
Rebalancing of ownership percentage between Company and Operating Partnership	0					4,270			(51)	(4,219)
Ending Balance (in shares) at Mar. 31, 2017				79,086,000	31,645,000
Ending Balance at Mar. 31, 2017	$ 1,481,313			$ 80	$ 32	$ 1,106,394	$ (24,501)	$ (39,697)	$ 4,834	$ 428,931	$ 5,240