CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Cumulative effect of the credit loss standard adoption, net of tax	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Common Stock Contingent Class A Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Retained Earnings Cumulative effect of the credit loss standard adoption, net of tax	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance at Dec. 31, 2018	$ 1,056,799		$ 1,570	$ 212	$ 3,250	$ 285,071	$ (486)	$ 277,952			$ 489,230
Increase (Decrease) in Stockholders' Equity
Consolidated net income	55,470							39,572			15,898
Dividends to common stockholders	(33,961)							(33,961)
Preferred dividend on exchangeable preferred partnership units								(6,448)			6,448
Earning distributions to limited partnership interests, redeemable partnership interests, and other noncontrolling interests	(41,521)										(41,521)
Grant of exchangeability, redemption and issuance	(13,862)		13			4,760					(18,635)
Issuance of limited partnership units including contingent units	7,021					2,363					4,658
Issuance and redemption of limited partnership units including contingent units					(294)	294
Repurchase of shares of Class A common stock	(13,896)						(13,896)
Restricted stock units compensation	1,466					1,466
Other	(1,513)					(1,513)
Ending balance at Jun. 30, 2019	1,016,003		1,583	212	2,956	292,441	(14,382)	277,115			456,078
Beginning balance at Mar. 31, 2019	1,020,798		1,574	212	3,141	284,054	(486)	275,589			456,714
Increase (Decrease) in Stockholders' Equity
Consolidated net income	32,064							22,668			9,396
Dividends to common stockholders	(17,918)							(17,918)
Preferred dividend on exchangeable preferred partnership units								(3,224)			3,224
Earning distributions to limited partnership interests, redeemable partnership interests, and other noncontrolling interests	(14,241)										(14,241)
Grant of exchangeability, redemption and issuance	1,668		9			5,332					(3,673)
Issuance of limited partnership units including contingent units	7,021					2,363					4,658
Issuance and redemption of limited partnership units including contingent units					(185)	185
Repurchase of shares of Class A common stock	(13,896)						(13,896)
Restricted stock units compensation	1,195					1,195
Other	(688)					(688)
Ending balance at Jun. 30, 2019	1,016,003		1,583	212	2,956	292,441	(14,382)	277,115			456,078
Beginning balance at Dec. 31, 2019	940,625	$ (19,023)	1,608	212	1,461	318,165	(34,894)	313,112	$ (19,023)		340,961
Increase (Decrease) in Stockholders' Equity
Consolidated net income	14,880							8,493			6,387
Other comprehensive income (loss), net of tax	(2,286)									$ (2,286)
Dividends to common stockholders	(19,563)							(19,563)
Preferred dividend on exchangeable preferred partnership units								(4,889)			4,889
Earning distributions to limited partnership interests, redeemable partnership interests, and other noncontrolling interests	(38,080)										(38,080)
Grant of exchangeability, redemption and issuance	2,126		15			6,663					(4,552)
Issuance and redemption of limited partnership units including contingent units	907				(411)	425					893
Restricted stock units compensation	4,923					3,322					1,601
Other	303					621				(318)
Ending balance at Jun. 30, 2020	884,812		1,623	212	1,050	329,196	(34,894)	278,130		(2,604)	312,099
Beginning balance at Mar. 31, 2020	920,933		1,612	212	1,050	324,817	(34,894)	282,053		(1,277)	347,360
Increase (Decrease) in Stockholders' Equity
Consolidated net income	644							314			330
Other comprehensive income (loss), net of tax	(1,009)									(1,009)
Dividends to common stockholders	(1,790)							(1,790)
Preferred dividend on exchangeable preferred partnership units								(2,447)			2,447
Earning distributions to limited partnership interests, redeemable partnership interests, and other noncontrolling interests	(37,130)										(37,130)
Grant of exchangeability, redemption and issuance	137		11			2,240					(2,114)
Restricted stock units compensation	2,724					1,518					1,206
Other	303					621				(318)
Ending balance at Jun. 30, 2020	$ 884,812		$ 1,623	$ 212	$ 1,050	$ 329,196	$ (34,894)	$ 278,130		$ (2,604)	$ 312,099