CONSOLIDATED STATEMENT OF EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock
Increase (Decrease) in Stockholders' Equity
Cumulative effect of adoption of new accounting standards	$ 2,264	$ 431	$ 1,833
BALANCE (shares) at Dec. 31, 2015							68,792,483		25,928,357
BALANCE at Dec. 31, 2015	499,678	962,726	(437,029)	$ (834)	$ (26,132)		$ 688		$ 259
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(32,781)		(32,781)
Repurchases of Class A Common Stock (in shares)							(384,700)
Repurchases of Class A Common Stock	(11,247)	(11,243)					$ (4)
Class A Common Stock issued pursuant to employee benefit plans (shares)							327,167
Repurchases of Class A Common Stock	12,907	12,904					$ 3
Distributions to noncontrolling interests	(4,370)				(4,370)
Issuance of subsidiary stock awards	214				214
Net income	76,229		73,559		2,670
BALANCE (shares) at Jun. 30, 2016							68,734,950		25,928,357
BALANCE at Jun. 30, 2016	542,894	964,818	(394,418)	(834)	(27,618)		$ 687		$ 259
BALANCE (shares) at Dec. 31, 2016						64,558,207	64,558,207	25,670,684	25,670,684
BALANCE at Dec. 31, 2016	557,936	843,691	(255,804)	(807)	(30,047)		$ 646		$ 257
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(34,744)		(34,744)
Class A Common Stock issued pursuant to employee benefit plans (shares)							435,619
Repurchases of Class A Common Stock	15,207	15,203					$ 4
Distributions to noncontrolling interests	(18,048)				(18,048)
Issuance of common stock, net of issuance costs (in shares)							12,000,000
Issuance of common stock, net of issuance costs	487,883	487,763					$ 120
Net income	116,738		101,847		14,891
BALANCE (shares) at Jun. 30, 2017						76,993,826	76,993,826	25,670,684	25,670,684
BALANCE at Jun. 30, 2017	$ 1,124,972	$ 1,346,657	$ (188,701)	$ (807)	$ (33,204)		$ 770		$ 257