CONSOLIDATED STATEMENT OF EQUITY (DEFICIT) (USD $) In Thousands, except Share data, unless otherwise specified	Total USD ($)	Additional Paid-In Capital USD ($)	Accumulated Deficit USD ($)	Accumulated Other Comprehensive Loss USD ($)	Noncontrolling Interests USD ($)	Class A Common Stock	Class A Common Stock Common Stock USD ($)	Class B Common Stock	Class B Common Stock Common Stock USD ($)
BALANCE at Dec. 31, 2011	$ (111,362)	$ 617,375	$ (734,511)	$ (4,848)	$ 9,813		$ 520		$ 289
BALANCE (in shares) at Dec. 31, 2011							52,022,086		28,933,859
Increase (Decrease) in Stockholders' Equity
Dividends declared on Class A and Class B Common Stock	(31,245)		(31,245)
Class A Common Stock issued pursuant to employee benefit plans	4,554	4,551					3
Class A Common Stock issued pursuant to employee benefit plans (in shares)							284,722
Tax benefit on share based awards	207	207
Distributions to noncontrolling interests	(734)				(734)
Issuance of subsidiary share awards	392				392
Amortization of net periodic pension benefit costs, net of taxes	246			246
Net income	85,558		85,664		(106)
BALANCE at Sep. 30, 2012	(52,384)	622,133	(680,092)	(4,602)	9,365		523		289
BALANCE (in shares) at Sep. 30, 2012							52,306,808		28,933,859
BALANCE at Dec. 31, 2012	(100,053)	600,928	(713,697)	(4,993)	16,897		523		289
BALANCE (in shares) at Dec. 31, 2012						52,332,012	52,332,012	28,933,859	28,933,859
Increase (Decrease) in Stockholders' Equity
Dividends declared on Class A and Class B Common Stock	(41,938)		(41,938)
Issuance of common stock, net of issuance costs	472,400	472,220					180
Issuance of common stock, net of issuance costs (in shares)							18,000,000
Class B Common Stock converted into Class A Common Stock							27		(27)
Class B Common Stock converted into Class A Common Stock (in shares)							2,671,649		(2,671,649)
4.875% Convertible Debentures converted into Class A Common Stock, net of taxes	7,313	7,310					3
4.875% Convertible Debentures converted into Class A Common Stock, net of taxes (in shares)							338,632
Class A Common Stock issued pursuant to employee benefit plans	9,479	9,129			344		6
Class A Common Stock issued pursuant to employee benefit plans (in shares)							558,149
Tax benefit on share based awards	503	503
Distributions to noncontrolling interests	(9,939)				(9,939)
Class A Common Stock sold by variable interest entity, net of taxes	7,008	7,008
Amortization of net periodic pension benefit costs, net of taxes	(116)			(116)
Net income	71,580		71,165		415
BALANCE at Sep. 30, 2013	$ 416,238	$ 1,097,098	$ (684,470)	$ (5,109)	$ 7,717		$ 739		$ 263
BALANCE (in shares) at Sep. 30, 2013						73,900,442	73,900,442	26,262,210	26,262,210