Earnings Per Common 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
Income Per Common Share - Basic:
Net income	$ 7,592	$ 5,562	$ 22,995	$ 12,671
Weighted-average common shares outstanding	44,131	43,921	44,109	43,782
Basic income per share (in dollars per share)	$ 0.17	$ 0.13	$ 0.52	$ 0.29
Income Per Common Share - Diluted:
Net income	7,592	5,562	22,995	12,671
Add-back of interest expense on outstanding convertible notes payable, net of tax	0	0	0	1,142
Adjusted net income	$ 7,592	$ 5,562	$ 22,995	$ 13,813
Weighted-average common shares outstanding	44,131	43,921	44,109	43,782
Weighted-average incremental shares related to assumed exercise of stock options, vesting of nonvested shares, and ESPP	108	216	145	172
Weighted-average incremental shares assuming conversion of outstanding notes payable	0	0	0	9,514	[1]
Weighted-average common shares outstanding and common share equivalents	44,239	44,137	44,254	53,468
Diluted income per share (in dollars per share)	$ 0.17	$ 0.13	$ 0.52	$ 0.26

[1] Dilutive convertible notes payable, which were retired on June 1, 2013, were included in the denominator of diluted EPS for the period that they were outstanding.