Convertible Notes and Non-recourse Notes (Narrative) (Detail) (USD $)	12 Months Ended			1 Months Ended				3 Months Ended	12 Months Ended							0 Months Ended	12 Months Ended				0 Months Ended	1 Months Ended		12 Months Ended				1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Series 2012 Notes [Member]	Sep. 30, 2012 Series 2012 Notes [Member]	Feb. 29, 2012 Series 2012 Notes [Member]	Jan. 31, 2012 Series 2012 Notes [Member]	Mar. 31, 2012 Series 2012 Notes [Member]	Dec. 31, 2012 Series 2012 Notes [Member]	Dec. 31, 2011 Series 2012 Notes [Member]	Dec. 31, 2010 Series 2012 Notes [Member]	Dec. 31, 2012 2012 Notes [Member]	Dec. 31, 2011 2012 Notes [Member]	Dec. 31, 2010 2012 Notes [Member]	Dec. 31, 2012 2023 Notes [Member]	Nov. 01, 2010 February 2015 Notes [Member]	Dec. 31, 2012 February 2015 Notes [Member]	Feb. 29, 2012 February 2015 Notes [Member]	Dec. 31, 2011 February 2015 Notes [Member]	Dec. 31, 2010 February 2015 Notes [Member]	May 16, 2011 May 2015 Notes [Member]	Dec. 31, 2012 May 2015 Notes [Member]	Sep. 30, 2012 May 2015 Notes [Member]	Dec. 31, 2012 May 2015 Notes [Member]	Dec. 31, 2011 May 2015 Notes [Member]	Dec. 31, 2010 May 2015 Notes [Member]	Dec. 31, 2012 Purchased Call Options and Warrants [Member]	Nov. 30, 2009 Non-recourse Notes [Member]	Dec. 31, 2012 Non-recourse Notes [Member]	Dec. 31, 2011 Non-recourse Notes [Member]	Dec. 31, 2010 Non-recourse Notes [Member]
Debt Instrument [Line Items]
Debt instrument, amount converted						$ 10,000,000	$ 169,000,000									$ 92,000,000												$ 300,000,000
Incentive fee per each $1,000 principal amount tendered to convert debt							5.00									5
Principal amount a $5 incentive cash payment per each to convert debt							1,000									1,000
Deferred costs							765,000												3,200,000
Debt instrument, face amount				179,000,000					179,000,000	0												155,250,000		155,250,000	155,250,000
Induced Conversion of Convertible Debt Expense							845,000
Proceeds from Convertible Debt	0	149,712,000	82,039,000																		149,700,000
Debt Instrument, Convertible, Conversion Ratio									169.525							169.525					148.3827
Debt Instrument, Convertible, Conversion Price (in Dollars per Share)				$ 5.90					$ 5.90	$ 5.90						$ 5.90					$ 6.74
Convertible notes repurchase price as a percentage of principal (in Percent)									98.00%							100.00%					100.00%
Debt issuance costs incurred during transaction								216,000	813,000	597,000
Debt instrument, interest rate (in Percent)				2.875%					2.875%			2.00%			2.75%		3.75%				3.75%	2.875%		2.875%				10.25%
Debt instrument, convertible, effective interest rate (in Percent)									7.30%															37.50%
Debt Instrument, Unamortized Discount	(16,833,000)			13,472,000					13,472,000	0		0					0		0			11,817,000		11,817,000	16,298,000				0
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	10,692,000	11,870,000					52,000		10,900,000															12,300,000
Noted obligation allocated to deferred tax liability							28,000		5,900,000															6,600,000			7,200,000
Number of hedge counterparties																											2
Option Indexed to Issuer's Equity, Shares (in Shares)																								27,500,000			21,100,000
Option Indexed to Issuer's Equity, Strike Price																								7.93			6.74
Debt Instrument, Convertible, Terms of Conversion Feature									If the closing price of common stock for at least 20 trading days in a period of 30 consecutive trading days exceeds 130% of conversion price.												If the closing price of common stock for at least 20 trading days in a period of 30 consecutive trading days exceeds 130% of conversion price.
Debt instrument, convertible, remaining amortization period (in Duration)									2 years 1 month 6 days								3 years 2 months 12 days							2 years 3 months 18 days
Purchased call options cost																											20,800,000
Debt instrument, convertible, conversion threshold (in Dollars per Share)				$ 7.67	$ 7.82																	$ 8.76	$ 8.94				$ 7.93
Debt instrument, convertible, if-converted value									34,600,000															6,900,000
Deferred taxes on purchased call options cost																											7,200,000
Number of shares of common stock covered by the purchased call options purchased (in Shares)																											1,900,000
Proceeds from Issuance of Warrants	0	10,868,000	0																					10,000,000			10,900,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in Shares)																											0
Gains (Losses) on Extinguishment of Debt	0	(766,000)	(17,648,000)													1,100,000
Debt Instrument, Increase, Additional Borrowings																88,000,000
Unamortized Debt Issuance Expense																			4,134,000						3,208,000
Debt Instrument, Convertible, Interest Expense									11,911,000	0	0													11,496,000	7,005,000	0
Repayments of Convertible Debt	0	133,851,000	108,247,000
Notes Payable	309,952,000	409,985,000	514,698,000	165,528,000					165,528,000	0	0	0	0	133,464,000			991,000		177,663,000	176,964,000		143,433,000		143,433,000	138,952,000	0			0	93,370,000	204,270,000
Securitization of Royalties																												60.00%
Debt instrument, aggregate principal outstanding																	$ 1,000,000	$ 1,000,000	$ 180,000,000