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		9 Months Ended				0 Months Ended	3 Months Ended			3 Months Ended	1 Months Ended	3 Months Ended	0 Months Ended	1 Months Ended
	Sep. 30, 2013	Jun. 30, 2014	May 16, 2011	Jan. 31, 2012 Series 2012 Notes [Member]	Sep. 30, 2013 Series 2012 Notes [Member]	Jun. 30, 2013 Series 2012 Notes [Member]	Sep. 30, 2013 Series 2012 Notes [Member]	Aug. 01, 2013 Series 2012 Notes [Member]	Dec. 31, 2012 Series 2012 Notes [Member]	Feb. 29, 2012 Series 2012 Notes [Member]	May 16, 2011 May 2015 Notes [Member]	Sep. 30, 2013 May 2015 Notes [Member]	Jun. 30, 2013 May 2015 Notes [Member]	Dec. 31, 2012 May 2015 Notes [Member]	Sep. 30, 2013 Purchased Call Options [Member]	Jan. 31, 2013 Warrants [Member]	Sep. 30, 2013 Warrants [Member]	Nov. 01, 2010 February 2015 Notes [Member]	Jan. 31, 2012 February 2015 Notes [Member]	Sep. 30, 2013 February 2015 Notes [Member]	Aug. 01, 2013 February 2015 Notes [Member]	Feb. 29, 2012 February 2015 Notes [Member]
Debt Instrument [Line Items]
Convertible notes										$ 10,000,000	$ 155,300,000							$ 92,000,000	$ 169,000,000		$ 1,000,000	$ 10,000,000
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
Induced conversion of convertible debt expense				845,000															800,000
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%								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)	(8,934,000)		(8,934,000)		(13,472,000)			(8,235,000)		(11,817,000)
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%
Debt Instrument, Interest Rate, Effective Percentage			7.50%	7.30%	7.30%		7.30%				7.50%
Convertible notes, conversion price (in Dollars per Share)					$ 5.56		$ 5.56					$ 6.35					$ 7.48
Debt instrument, convertible, remaining amortization period (in Duration)							1 year 4 months 18 days					1 year 7 months 3 days
Debt instrument, convertible, conversion threshold (in Dollars per Share)					$ 7.23	$ 7.37						$ 8.26	$ 8.42
Debt instrument, convertible, if-converted value							77,900,000					39,500,000
Net proceeds from the issuance of convertible notes											149,700,000
Convertible notes repurchase price as a percentage of principal (in Percent)											100.00%
Debt Instrument, Face Amount					180,000,000		180,000,000	180,000,000	179,000,000			155,250,000		155,250,000						0
Conversion Rate per $1,000 Principal Amount (in Ratio)					179.7770							157.3700
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