Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings per common share:
Net income attributable to common stockholders-Basic	$ 13,178	$ 2,126	$ 16,784	$ 7,632
Impact of assumed conversions:
Interest on convertible notes	570
Dividends, Preferred Stock				140
Net income attributable to common stockholders-Diluted	$ 13,748	$ 2,126	$ 16,784	$ 7,772
Weighted average common shares outstanding-Basic	48,227	44,749	47,890	41,180
Assumed conversions:
Assumed conversions: Incremental common shares from warrants	1,657	1,900	1,678	2,724
Assumed conversions: Incremental common shares from stock options	983	784	977	743
Assumed conversions: Incremental common shares from convertible preferred stock before conversion				876
Assumed conversions: Incremental common shares from restricted stock units	73		41
Assumed conversions: Incremental common shares from convertible senior notes	3,092
Weighted average common shares outstanding Diluted	54,032	47,433	50,586	45,523
Basic earnings per common share	$ 0.27	$ 0.05	$ 0.35	$ 0.19
Diluted earnings per common share	$ 0.25	$ 0.04	$ 0.33	$ 0.17