Debt 4.25% Convertible Senior Notes (Details) (USD $)	3 Months Ended
	Aug. 14, 2016	Mar. 31, 2013	Mar. 31, 2012	May 20, 2016	Dec. 31, 2012
Debt Instrument [Line Items]
Stated interest rate on debt instrument			4.25%
Conversion price (in usd per share)		$ 22.45	$ 22.45
Amortization of discount on the debt component		$ 2,619,000	$ 2,320,000
4.25% Convertible senior notes [Member]
Debt Instrument [Line Items]
Stated interest rate on debt instrument		4.25%
Face amount of convertible notes		200,000,000	200,000,000		200,000,000
Number of shares to be issued per $1,000 of $.25% convertible notes	44.5524
Principal amount of note to be considered under conversion rate	1,000
Conversion price (in usd per share)				$ 22.45
Effective interest rate		12.50%
Unamortized discount		(44,299,000)	(54,313,000)		(46,918,000)
Net carrying amount of debt component		155,701,000	145,687,000		153,082,000
Equity component		84,904,000	84,904,000		84,904,000
Issuance costs and income taxes related to convertible debt		(3,210,000)	(3,210,000)		(3,210,000)
Equity component, net of issuance costs and income taxes		81,694,000	81,694,000		81,694,000
4.25% coupon interest		2,125,000	2,125,000
Amortization of deferred financing fees		117,000	117,000
Amortization of discount on the debt component		2,619,000	2,320,000
Interest expense related to the convertible notes		$ 4,861,000	$ 4,562,000