Summary of Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Income from continuing operations	$ 11,593	$ 7,953	$ 17,378	$ 12,342
Income from discontinued operations, net of tax	0	2,750	0	4,610
Net income	$ 11,593	$ 10,703	$ 17,378	$ 16,952
Denominator:
Weighted average shares outstanding – basic (in shares)	28,134	32,481	28,204	32,729
Common stock equivalents (in shares)	203	229	203	215
Weighted average shares outstanding – diluted (in shares)	28,337	32,710	28,407	32,944
Earnings per share – basic:
From continuing operations (in dollars per share)	$ 0.41	$ 0.24	$ 0.62	$ 0.38
From discontinued operations (in dollars per share)	0.00	0.09	0.00	0.14
Earnings per share – basic (in dollars per share)	0.41	0.33	0.62	0.52
Earnings per share – diluted:
From continuing operations (in dollars per share)	0.41	0.24	0.61	0.37
From discontinued operations (in dollars per share)	0.00	0.09	0.00	0.14
Earnings per share – diluted (in dollars per share)	$ 0.41	$ 0.33	$ 0.61	$ 0.51