Earnings per Share Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share Calculation [Line Items]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 13,617	$ 125,311	$ 39,803	$ 137,162
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Preferred Dividends	(1,218)	(1,219)	(3,656)	(2,438)
Preferred Stock Redemption Premium	0	0	0	(2,190)
Net income to common shareholders	12,399	124,092	36,147	132,534
Net Income (Loss) Available to Common Stockholders, Diluted	13,263	125,527	38,754	136,218
Weighted Average Number of Shares Outstanding, Basic	24,474	24,358	24,454	23,642
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Stock Options	214	183	223	246
Incremental Common Shares Attributable to Deferred Compensation	148	119	138	111
Weighted Average Number of Shares Outstanding, Diluted	29,921	29,745	29,900	28,410
Earnings Per Share, Basic	$ 0.51	$ 5.09	$ 1.48	$ 5.61
Earnings Per Share, Diluted	$ 0.44	$ 4.22	$ 1.30	$ 4.79
Anti-dilutive stock equivalent awards not included in the calculation of diluted loss per share	1,286	998	1,243	951
2017 Convertible Senior Notes [Member]
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Interest on Convertible Debt, Net of Tax	368	611	1,110	1,833
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Conversion of Debt Securities	2,416	2,416	2,416	2,416
2018 Convertible Senior Notes [Member]
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Interest on Convertible Debt, Net of Tax	$ 496	$ 824	$ 1,497	$ 1,851
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Conversion of Debt Securities	2,669	2,669	2,669	1,995