Quarterly Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended	3 Months Ended							12 Months Ended		3 Months Ended							12 Months Ended		3 Months Ended							12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011	Sep. 30, 2011 Scenario, Previously Reported [Member]	Jun. 30, 2011 Scenario, Previously Reported [Member]	Mar. 31, 2011 Scenario, Previously Reported [Member]	Dec. 31, 2010 Scenario, Previously Reported [Member]	Sep. 30, 2010 Scenario, Previously Reported [Member]	Jun. 30, 2010 Scenario, Previously Reported [Member]	Mar. 31, 2010 Scenario, Previously Reported [Member]	Dec. 31, 2010 Scenario, Previously Reported [Member]	Dec. 31, 2009 Scenario, Previously Reported [Member]	Sep. 30, 2011 Restatement Adjustment [Member]	Jun. 30, 2011 Restatement Adjustment [Member]	Mar. 31, 2011 Restatement Adjustment [Member]	Dec. 31, 2010 Restatement Adjustment [Member]	Sep. 30, 2010 Restatement Adjustment [Member]	Jun. 30, 2010 Restatement Adjustment [Member]	Mar. 31, 2010 Restatement Adjustment [Member]	Dec. 31, 2010 Restatement Adjustment [Member]	Dec. 31, 2009 Restatement Adjustment [Member]	Sep. 30, 2011 As Restated [Member]	Jun. 30, 2011 As Restated [Member]	Mar. 31, 2011 As Restated [Member]	Dec. 31, 2010 As Restated [Member]	Sep. 30, 2010 As Restated [Member]	Jun. 30, 2010 As Restated [Member]	Mar. 31, 2010 As Restated [Member]	Dec. 31, 2010 As Restated [Member]		Dec. 31, 2009 As Restated [Member]
Quarterly Financial Information [Line Items]
Total revenues	$ 185,104	$ 691,243	$ 171,563	$ 162,410	$ 163,606	$ 168,762	$ 158,443	$ 158,373	$ 131,631	$ 617,209	$ 385,800	$ 1,536	$ 3,112	$ 3,912	$ (5,853)	$ (2,459)	$ (9,806)	$ (5,349)	$ (23,467)	$ 5,168	$ 173,099	$ 165,522	$ 167,518	$ 162,909	$ 155,984	$ 148,567	$ 126,282	$ 593,742	[1]	$ 390,968	[1]
Gross Profit	119,739	419,690	104,270	90,637	95,515	101,326	87,323	96,126	78,900	363,675	240,129	1,902	3,414	4,213	(6,378)	731	(12,206)	(6,826)	(24,679)	5,414	106,172	94,051	99,728	94,948	88,054	83,920	72,074	338,996	[1]	245,543	[1]
Operating income (loss)	7,477	(124,328)	32,832	19,121	54,291	12,090	17,535	17,056	(253)	(46,428)	(39,880)	2,692	3,929	3,986	6,260	(850)	11,378	8,281	25,069	(5,613)	35,524	23,050	58,277	5,830	18,385	5,678	(8,534)	(21,359)	[1]	(45,493)	[1]
Income (loss) applicable to common shareholders	$ 3,575	$ (82,688)	$ 16,803	$ 10,119	$ 45,528	$ 5,847	$ 8,273	$ 7,866	$ (4,268)	$ (17,718)	$ (17,746)	$ 1,484	$ 2,594	$ 2,585	$ 1,848	$ (590)	$ 8,297	$ 6,022	$ 15,577	$ (1,236)	$ 18,287	$ 12,713	$ 48,113	$ 3,999	$ 8,863	$ (431)	$ (10,290)	$ (2,141)	[1]	$ (18,982)	[1]
Basic net income (loss) per common share (price per share)	$ 0.08	$ 1.95	$ 0.40	$ 0.24	$ 1.08	$ 0.14	$ 0.20	$ 0.19	$ (0.11)	$ 0.43	$ 0.51	$ 0.03	$ 0.06	$ 0.06	$ (0.04)	$ 0.01	$ (0.20)	$ (0.15)	$ (0.38)	$ 0.03	$ 0.43	$ 0.30	$ 1.14	$ 0.10	$ 0.21	$ (0.01)	$ (0.26)	$ 0.05	[1]	$ 0.54	[1]
Diluted net income (loss) per common share (price per share)	$ 0.08	$ 1.93	$ 0.39	$ 0.24	$ 1.07	$ 0.14	$ 0.20	$ 0.19	$ (0.11)	$ 0.42	$ 0.50	$ 0.04	$ 0.06	$ 0.06	$ (0.05)	$ 0.01	$ (0.20)	$ (0.15)	$ (0.37)	$ 0.04	$ 0.43	$ 0.30	$ 1.13	$ 0.09	$ 0.21	$ (0.01)	$ (0.26)	$ 0.05	[1]	$ 0.54	[1]

[1] As restated - See Note 23 “Restatement of Previously Issued Financial Statements” of Notes to Consolidated Financial Statements.