Earnings Per Share - Basic and Diluted Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Net income - Basic	$ 8,968	$ 9,806	$ 25,173	$ 26,590
Interest on convertible notes	0	414	0	0
Net income - Diluted	$ 8,968	$ 10,220	$ 25,173	$ 26,590
Weighted average common shares outstanding - Basic	52,742	48,384	50,819	48,054
Assumed conversions:
Incremental common shares from warrants	1,365	1,493	1,404	1,617
Incremental common shares from stock options	1,134	1,003	1,143	986
Incremental common shares from restricted stock units	76	158	41	80
Incremental common shares from convertible senior notes	0	2,440	0	0
Weighted average common shares outstanding - Diluted	55,317	53,478	53,407	50,737
Basic earnings per common share	$ 0.17	$ 0.20	$ 0.50	$ 0.55
Diluted earnings per common share	$ 0.16	$ 0.19	$ 0.47	$ 0.52