CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Adjustments	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 Adjustments	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	178,039							128,270			49,769
Dividends to common stockholders	(51,659)							(51,659)
Preferred dividends on exchangeable preferred partnership units	0							(9,672)			9,672
Earnings distributions to limited partnership interests and other noncontrolling interests	(67,622)										(67,622)
Grant of exchangeability, redemption and issuance	(13,180)		20			7,632					(20,832)
Issuance of limited partnership units including contingent units	2,715					914					1,801
Issuance and redemption of limited partnership units including contingent units	(33,983)						(33,983)
Repurchase of shares of Class A common stock	0
Redemption of EPUs	(93,480)										(93,480)
Other	1,284					1,284
Ending balance at Sep. 30, 2019	978,913		1,590	212	3,250	294,901	(34,469)	344,891			368,538
Beginning balance at Jun. 30, 2019	1,016,003		1,583	212	2,956	292,441	(14,382)	277,115			456,078
Increase (Decrease) in Stockholders' Equity
Consolidated net income	122,569							88,698			33,871
Dividends to common stockholders	(17,698)							(17,698)
Preferred dividends on exchangeable preferred partnership units	0							(3,224)			3,224
Earnings distributions to limited partnership interests and other noncontrolling interests	(26,101)										(26,101)
Grant of exchangeability, redemption and issuance	682		7			2,872					(2,197)
Issuance of limited partnership units including contingent units	2,715				294	620					1,801
Issuance and redemption of limited partnership units including contingent units	(20,087)						(20,087)
Repurchase of shares of Class A common stock	(7,021)					(2,363)					(4,658)
Restricted stock units compensation	(1,466)					(1,466)
Redemption of EPUs	(93,480)										(93,480)
Other	2,797					2,797
Ending balance at Sep. 30, 2019	978,913		1,590	212	3,250	294,901	(34,469)	344,891			368,538
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	114,404							83,841			30,563
Other comprehensive income (loss), net of tax	(3,421)									$ (3,421)
Dividends to common stockholders	(21,362)							(21,362)
Preferred dividends on exchangeable preferred partnership units	0							(8,138)			8,138
Earnings distributions to limited partnership interests and other noncontrolling interests	(44,609)										(44,609)
Grant of exchangeability, redemption and issuance	7,405		24			11,188					(3,807)
Issuance and redemption of limited partnership units including contingent units	907				(301)	315					893
Restricted stock units compensation	8,289					5,587					2,702
Redemption of EPUs	(93,480)										(93,480)
Other	382					700				(318)
Ending balance at Sep. 30, 2020	890,117		1,632	212	1,160	335,955	(34,894)	348,430		(3,739)	241,361
Beginning balance at Jun. 30, 2020	884,812		1,623	212	1,050	329,196	(34,894)	278,130		(2,604)	312,099
Increase (Decrease) in Stockholders' Equity
Consolidated net income	99,525							75,349			24,176
Other comprehensive income (loss), net of tax	(1,135)
Dividends to common stockholders	(1,799)							(1,799)
Preferred dividends on exchangeable preferred partnership units	0							(3,250)			3,250
Earnings distributions to limited partnership interests and other noncontrolling interests	(6,530)										(6,530)
Grant of exchangeability, redemption and issuance	5,279		9			4,525					745
Issuance and redemption of limited partnership units including contingent units					110	(110)
Restricted stock units compensation	3,366					2,265					1,101
Redemption of EPUs	(93,480)										(93,480)
Other	79					79
Ending balance at Sep. 30, 2020	$ 890,117		$ 1,632	$ 212	$ 1,160	$ 335,955	$ (34,894)	$ 348,430		$ (3,739)	$ 241,361