Convertible Notes, Exchangeble Notes and Trust Preferred Securities (Details) (USD $)	3 Months Ended	12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended
	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Convertible Notes, Exchangeable Notes, and Trust Preferred Securities [Member]		Dec. 31, 2011 Six Percent Convertible Guaranteed Note [Member]	Dec. 31, 2010 Six Percent Convertible Guaranteed Note [Member]	Dec. 31, 2009 Six Percent Convertible Guaranteed Note [Member]	Mar. 31, 2010 Six Percent Convertible Guaranteed Note [Member]	Dec. 31, 2011 Five Percent Exchangeable Guaranteed Note [Member]	Dec. 31, 2010 Five Percent Exchangeable Guaranteed Note [Member]	Dec. 31, 2009 Five Percent Exchangeable Guaranteed Note [Member]	Dec. 31, 2007 Five Percent Exchangeable Guaranteed Note [Member]	Dec. 31, 2007 Six Point Eight Zero Four Percent Trust Preferred Securities [Member]	Dec. 31, 2011 Six Point Eight Zero Four Percent Trust Preferred Securities [Member]	Dec. 31, 2010 Six Point Eight Zero Four Percent Trust Preferred Securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of notes required to be repurchased at the option of the holders on set dates	100.00%
Convertible debt conversion ratio						142.6917
Convertible debt conversion price						$ 7.01
Exchangeable note exchange price													$ 19.49
Original debt conversion amount											25,500,000	123,350,000
Repurchase of exchangeable notes		0	25,493,000								25,493,000	101,006,000
Debt satisfaction gains (charges)											(760,000)	17,355,000
Write-offs of debt discount and deferred financing costs											768,000	4,989,000
Carrying amount of debt component						105,149,000	103,211,000			62,102,000	61,438,000
Carrying amount of equity component						13,134,000	13,134,000			20,293,000	20,293,000
Effective interest rate						8.10%	7.50%			7.00%	7.00%
Aggregate if-converted value in excess of aggregate principal amount						7,907,000	14,036,000			0	0
Coupon interest						6,900,000	6,408,000	0		3,387,000	3,504,000	7,554,000
Discount amortization						1,938,000	1,776,000	0		664,000	689,000	1,479,000
Interest Expense						8,838,000	8,184,000	0		4,051,000	4,193,000	9,033,000
Scheduled Principal Payments for Debt Instruments [Abstract]
2012				62,150,000
2013				0	[1]
2014				0
2015				0
2016				0
Thereafter				244,120,000
Long-term Debt, Gross				306,270,000
Long-term debt				296,371,000
Debt discount				(9,899,000)		(9,851,000)	(11,789,000)			(48,000)	(712,000)
Debt instrument amount						115,000,000	115,000,000		115,000,000	62,150,000	62,150,000		450,000,000	200,000,000
Debt interest rate percentage									6.00%				5.45%	6.80%
Description of variable rate basis														three month LIBOR plus 170 basis points
Basis spread on variable rate														1.70%
Principal amount outstanding on Trust Preferred Securities															$ 129,120,000	$ 129,120,000

[1] Although the 5.45% Exchangeable Guaranteed Notes matured in 2027, the notes were put to the Company in 2012.