Convertible Notes (Narrative) (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended				0 Months Ended	3 Months Ended			3 Months Ended	1 Months Ended	3 Months Ended	0 Months Ended	1 Months Ended	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2014	Jan. 31, 2012 Series 2012 Notes [Member]	Jun. 30, 2013 Series 2012 Notes [Member]	Mar. 31, 2013 Series 2012 Notes [Member]	Jun. 30, 2013 Series 2012 Notes [Member]	Dec. 31, 2012 Series 2012 Notes [Member]	Feb. 29, 2012 Series 2012 Notes [Member]	Feb. 02, 2012 Series 2012 Notes [Member]	May 16, 2011 May 2015 Notes [Member]	Jun. 30, 2013 May 2015 Notes [Member]	Mar. 31, 2013 May 2015 Notes [Member]	Dec. 31, 2012 May 2015 Notes [Member]	Jun. 30, 2013 Purchased Call Options [Member]	Jan. 31, 2013 Warrants [Member]	Jun. 30, 2013 Warrants [Member]	Nov. 01, 2010 February 2015 Notes [Member]	Jan. 31, 2012 February 2015 Notes [Member]	Jun. 30, 2013 February 2015 Notes [Member]	Dec. 31, 2012 February 2015 Notes [Member]	Mar. 31, 2012 February 2015 Notes [Member]	Feb. 29, 2012 February 2015 Notes [Member]	Feb. 02, 2012 February 2015 Notes [Member]
Debt Instrument [Line Items]
Convertible notes								$ 10,000,000	$ 179,000,000	$ 155,300,000							$ 92,000,000	$ 169,000,000			$ 1,000,000	$ 10,000,000	$ 1,000,000
Incentive fee per each $1,000 principal amount tendered to convert debt																		5.00
Principal amount a $5 incentive cash payment per each to convert debt	1,000		1,000	1,000														1,000	1,000
Induced conversion of convertible debt expense			845,000															800,000
Unamortized debt issuance expense																			9,000	12,000
Deferred issue costs, incentive payment allocated			765,000
Adjustments to additional paid in capital, equity component of convertible debt			52,000			10,900,000					12,300,000
Noted obligation allocated to deferred tax assets			28,000			5,900,000					6,600,000
Debt instrument, interest rate (in Percent)			2.875%	7.30%		7.30%					3.75%							2.875%
Convertible note rate conversion trading days (in days)	0
Convertible Notes rate conversion consecutive trading days (in days)	30
Convertible notes due upon demand within (in years)		1
Total debt discount											18,900,000								16,800,000
Unamortized discount of liability component			(2,300,000)	(10,472,000)		(10,472,000)	(13,472,000)				(9,451,000)		(11,817,000)						(7,000)	(9,000)
Debt instrument, convertible, effective interest rate (in Percent)	7.50%					7.30%					7.50%
Minimum conversion price percent for note conversion (in Percent)			130.00%								130.00%
Convertible Notes rate conversion business day period (in days)	5
Convertible Notes rate conversion consecutive trading day period (in days)	0
Maximum percent of common stock closing price and conversion rate to convert note (in Percent)			98.00%								98.00%
Convertible notes, conversion price (in Dollars per Share)				$ 5.67		$ 5.67					$ 6.48					$ 7.62			$ 5.67
Debt instrument, convertible, remaining amortization period (in Duration)						1 year 7 months 6 days					1 year 9 months 18 days
Debt instrument, convertible, conversion threshold (in Dollars per Share)				$ 7.37	$ 7.51						$ 8.42	$ 8.57
Debt instrument, convertible, if-converted value						64,700,000					29,800,000
Net proceeds from the issuance of convertible notes										149,700,000
Convertible notes repurchase price as a percentage of principal (in Percent)										100.00%									100.00%
Debt Instrument, Face Amount				179,000,000		179,000,000	179,000,000				155,250,000		155,250,000						1,000,000
Conversion Rate per $1,000 Principal Amount (in Ratio)				176.3890							154.4189								176.3890
Number of hedge counterparties (in Counterparties)														2
Purchased call options cost														20,800,000
Number of shares of common stock covered by the purchased call options purchased (in Shares)														24.0		27.5
Proceeds from issue of warrants															10,900,000	10,900,000
Debt conversion, shares issued (in Shares)																1.9
Deferred taxes included in purchased call options cost														7,200,000
Gain on conversion of convertible notes																	1,100,000
Debt instrument, increase, additional borrowings																	$ 88,000,000