Senior Notes, Convertible Notes, Exchangeable Notes and Trust Preferred Securities (Details) (USD $)	12 Months Ended						12 Months Ended				12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Senior Notes, Convertible Notes, Exchangeable Notes, and Trust Preferred Securities [Member]		Dec. 31, 2013 Six Percent Convertible Guaranteed Note [Member]	Dec. 31, 2012 Six Percent Convertible Guaranteed Note [Member]	Dec. 31, 2011 Six Percent Convertible Guaranteed Note [Member]	Dec. 31, 2010 Six Percent Convertible Guaranteed Note [Member]	Dec. 31, 2013 Five Percent Exchangeable Guaranteed Note [Member]	Dec. 31, 2012 Five Percent Exchangeable Guaranteed Note [Member]	Dec. 31, 2011 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, 2013 Six Point Eight Zero Four Percent Trust Preferred Securities [Member]	Dec. 31, 2012 Six Point Eight Zero Four Percent Trust Preferred Securities [Member]	Jun. 30, 2013 Senior Notes Due 2023 [Member] Senior Notes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Basis spread on variable rate															1.70%
Debt Instrument, Description of Variable Rate Basis															three month LIBOR plus 170 basis points
Debt Conversion, Converted Instrument, Cash Payment During Conversion	$ 3,270,000	$ 2,427,000
Debt Conversion, Converted Instrument, Debt Satisfaction Expense	13,536,000	7,842,000
Debt instrument amount							28,991,000	83,896,000		115,000,000				450,000,000	200,000,000			250,000,000
Debt Instrument, Percentage of Issuance Price																		99.026%
Debt interest rate percentage							6.00%	6.00%	6.00%	6.00%				5.45%	6.804%			4.25%
Percent of notes required to be repurchased at the option of the holders on set dates				100.00%
Convertible debt conversion ratio							147.8206
Convertible debt conversion price							$ 6.76
Repurchase of exchangeable notes	0	62,150,000	0									62,150,000
Debt satisfaction gains (charges)												(44,000)
Carrying amount of debt component							27,491,000	78,127,000
Carrying amount of equity component							(26,032,000)	3,654,000
Effective interest rate							8.10%	8.10%
Debt Conversion, Converted Instrument, Amount	54,905,000	31,104,000
Stock Issued During Period, Shares, Conversion of Convertible Securities	7,944,673	4,487,060
Aggregate if-converted value in excess of aggregate principal amount							14,296,000	42,579,000
Coupon interest							2,296,000	6,634,000	6,900,000		0	188,000	3,387,000
Discount amortization							658,000	1,868,000	1,938,000		0	34,000	664,000
Interest Expense							2,954,000	8,502,000	8,838,000		0	222,000	4,051,000
Principal amount outstanding on Trust Preferred Securities																129,120,000	129,120,000
Scheduled Principal Payments for Debt Instruments [Abstract]
2014					0
2015					0
2016					0
2017					28,991,000	[1]
2018					0
Thereafter					379,120,000
Long-term Debt, Gross					408,111,000
Debt discounts					(3,793,000)		(1,500,000)	(5,769,000)										(2,435,000)
Long-term debt					$ 404,318,000

[1] Although the 6.00% Convertible Guaranteed Notes mature in 2030, the notes can be put to the Company in 2017.