Earnings Per Share - Basic and Diluted Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Net income - Basic	$ 8,440	$ 13,178	$ 16,205	$ 16,784
Interest on convertible notes	0	570	0	0
Net income - Diluted	$ 8,440	$ 13,748	$ 16,205	$ 16,784
Weighted average common shares outstanding - Basic	51,086	48,227	49,841	47,890
Assumed conversions:
Incremental common shares from warrants	1,429	1,657	1,421	1,678
Incremental common shares from stock options	1,174	983	1,167	977
Incremental common shares from restricted stock units	24	73	16	41
Incremental common shares from convertible senior notes	0	3,092	0	0
Weighted average common shares outstanding - Diluted	53,713	54,032	52,445	50,586
Basic earnings per common share	$ 0.17	$ 0.27	$ 0.33	$ 0.35
Diluted earnings per common share	$ 0.16	$ 0.25	$ 0.31	$ 0.33