Earnings per Share Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss)									$ 151,423	$ 13,347	$ (33,877)
Preferred Stock Dividends, Income Statement Impact									(3,656)	0	0
Excess of fair value over book value of preferred shares redeemed									(2,190)	0	0
Net Income (Loss) Available to Common Stockholders, Basic									145,577	13,347	(33,877)
Net income (loss) available to common shareholders									150,695	13,347	(33,877)
Basic Weighted Average Shares Outstanding	24,358	24,358	24,271	22,273	21,545	19,434	18,833	18,772	23,822	19,651	18,698
Stock option awards									237	92	0
Deferred compensation awards									123	148	0
Diluted Weighted Average Shares Outstanding	29,783	29,745	24,646	22,688	21,961	20,273	19,031	18,772	28,763	19,891	18,698
Earnings Per Share, Basic	$ 0.54	$ 5.09	$ 0.25	$ 0.11	$ 0.23	$ 0.43	$ 0.17	$ (0.17)	$ 6.11	$ 0.68	$ (1.81)
Earnings Per Share, Diluted	$ 0.48	$ 4.22	$ 0.25	$ 0.11	$ 0.23	$ 0.42	$ 0.17	$ (0.17)	$ 5.24	$ 0.67	$ (1.81)
Anti-dilutive stock equivalent awards not included in the calculation of diluted loss per share									963	1,538	2,170
2018 Convertible Senior Notes [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Interest on 3.25% convertible senior subordinated notes due 2017									2,675	0	0
Convertible senior subordinated notes potential shares									2,165	0	0
2017 Convertible Senior Notes [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Interest on 3.25% convertible senior subordinated notes due 2017									$ 2,443	$ 0	$ 0
Convertible senior subordinated notes potential shares									2,416	0	0