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)	Operating Partnership	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	0
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)				$ 0			(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			10,521,149	10,521,149	10,521,000	(10,521,000)
Exchange of noncontrolling interest for common stock	0				$ 10	$ (10)	144,629			1,202	(145,831)
Adjustments to Additional Paid in Capital, Adjustment to Tax Receivable Agreement as Result of Exchange of Class B Share	(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
Contributions	7,479										0	7,479
Distributions	(42,524)										(42,218)	(306)
Equity based compensation	18,965						18,965
Grants of restricted stock (in shares)					1,997,000
Grants of restricted stock	0				$ 1		(1)
Purchase of treasury stock (in shares)					(190,000)
Purchase of treasury stock	(2,588)							(2,588)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units (in shares)					(1,323,000)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units	(18,125)				$ (1)			(18,124)
Forfeitures (in shares)					(10,000)
Forfeitures	0
Dividends declared	(105,921)								(105,921)
Stock dividends (in shares)					814,000	432,000
Stock dividends	0				$ 1	$ 1	17,317		(17,319)
Exchange of noncontrolling interest for common stock			20,767,407	20,767,407	20,767,000	(20,767,000)
Exchange of noncontrolling interest for common stock	(2,353)				$ 21	$ (21)	280,714			1,696	(284,763)
Net income (loss)	125,879								95,276		30,377	226
Other comprehensive income (loss)	(2,220)									(2,915)	695
Rebalancing of ownership percentage between Company and Operating Partnership	0						(3,166)			(358)	3,524
Ending Balance (in shares) at Dec. 31, 2017					93,641,000	17,668,000
Ending Balance at Dec. 31, 2017	1,488,146	[1]			$ 94	$ 18	1,306,136	(31,956)	(39,112)	(212)	240,861	12,317
Increase Decrease in Stockholders' Equity
Contributions	7,604										0	7,604
Distributions	(46,083)										(20,353)	(25,730)
Equity based compensation	8,831						8,831
Issuance of common stock (in shares)					5,800,000
Issuance of common stock	99,006				$ 6		99,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(499)						(499)
Grants of restricted stock (in shares)					34,000
Grants of restricted stock	0						0
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units (in shares)					(58,000)
Shares acquired to satisfy minimum required federal and state tax withholding on vesting restricted stock and units	(859)							(859)
Forfeitures (in shares)					(26,000)
Forfeitures	0
Dividends declared	(129,561)								(129,561)
Exchange of noncontrolling interest for common stock			4,549,832	4,549,832	4,550,000	(4,550,000)
Exchange of noncontrolling interest for common stock	515				$ 5	$ (5)	63,109			(167)	(62,427)
Net income (loss)	221,676								180,015		25,797	15,864
Other comprehensive income (loss)	(5,141)									(4,211)	(930)
Rebalancing of ownership percentage between Company and Operating Partnership	0						(5,420)			(59)	5,479
Ending Balance (in shares) at Dec. 31, 2018					103,941,000	13,118,000
Ending Balance at Dec. 31, 2018	$ 1,643,635	[1]			$ 105	$ 13	$ 1,471,157	$ (32,815)	$ 11,342	$ (4,649)	$ 188,427	$ 10,055

[1] Includes amounts relating to consolidated variable interest entities. See Note 3.