Earnings Per Common 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
Income (loss) Per Common Share - Basic:
Net income (loss)	$ 4,719		$ (729)		$ 7,109		$ (1,800)
Weighted-average common shares outstanding	43,729		48,176		43,711		48,234
Basic income (loss) per share (in dollars per share)	$ 0.11		$ (0.02)		$ 0.16		$ (0.04)
Income (loss) Per Common Share - Diluted:
Net income (loss)	4,719		(729)		7,109		(1,800)
Add-back of interest expense on outstanding convertible notes payable, net of tax	457		0	[1]	1,142		0	[1]
Adjusted net income (loss)	$ 5,176		$ (729)		$ 8,251		$ (1,800)
Weighted-average common shares outstanding	43,729		48,176		43,711		48,234
Weighted-average incremental shares related to assumed exercise of stock options, vesting of nonvested shares, and ESPP	126		0	[1]	215		0	[1]
Weighted-average incremental shares assuming conversion of outstanding notes payable	11,417	[2]	0	[1]	14,271	[2]	0	[1]
Weighted-average common shares outstanding and common share equivalents	55,272		48,176		58,197		48,234
Diluted income (loss) per share (in dollars per share)	$ 0.09		$ (0.02)		$ 0.14		$ (0.04)

[1] For the three and six months ended June 30, 2012, the Company recorded a net loss which could not be diluted.

[2] 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.