CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member] Class A [Member]	Common Stock [Member] Class B [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2010	$ 216,744	$ 71	$ 6	$ 1,505,971	$ 63,495	$ (1,352,799)
Balances (in shares) at Dec. 31, 2010		7,106,330	566,112
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,173	0	0	0	0	15,173
Issuance of Class A common stock	545	0	0	545	0	0
Issuance of Class A common stock (in shares)		29,147
Repurchase of Class A common stock	(229)	0	0	(229)	0	0
Repurchase of Class A common stock (in shares)		(8,910)
Forfeitures of Class A common stock	(770)	0	0	(770)	0	0
Forfeitures of Class A common stock (in shares)		(27,231)
Amortization of Class A common shares issued as stock-based awards	601	0	0	601	0	0
Reclassification of restricted stock units issued as stock based awards	2,595	0	0	2,595	0	0
Other comprehensive income
Net change in unrealized gain on available-for-sale investment securities	(25,128)	0	0	0	(25,128)	0
Dividends declared	(26,159)	0	0	0	0	(26,159)
Balances at Dec. 31, 2011	183,372	71	6	1,508,713	38,367	(1,363,785)
Balances (in shares) at Dec. 31, 2011		7,099,336	566,112
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	10,762	0	0	0	0	10,762
Issuance of Class A common stock	40,092	17	0	40,075	0	0
Issuance of Class A common stock (in shares)		1,755,000
Forfeitures of Class A common stock	(45)	0	0	(45)	0	0
Forfeitures of Class A common stock (in shares)		(1,915)
Amortization of Class A common shares issued as stock-based awards	160	0	0	160	0	0
Other comprehensive income
Net change in unrealized gain on available-for-sale investment securities	(4,903)	0	0	0	(4,903)	0
Dividends declared	(8,319)	0	0	0	0	(8,319)
Balances at Mar. 31, 2012	$ 221,119	$ 88	$ 6	$ 1,548,903	$ 33,464	$ (1,361,342)
Balances (in shares) at Mar. 31, 2012		8,852,421	566,112