Summary of Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Income from continuing operations	$ 11,901	$ 13,545	$ 11,593	$ 5,785	$ 9,061	$ 7,995	$ 7,953	$ 4,389	$ 42,824	$ 29,398	$ 5,294
Income from discontinued operations, net of tax	0	0	0	0	(116)	57,023	2,750	1,860	0	61,517	5,493
Net income	$ 11,901	$ 13,545	$ 11,593	$ 5,785	$ 8,945	$ 65,018	$ 10,703	$ 6,249	$ 42,824	$ 90,915	$ 10,787
Denominator:
Weighted average shares outstanding - basic (in shares)									27,910	31,475	33,511
Common stock equivalents (in shares)									280	216	132
Weighted average shares outstanding – diluted (in shares)									28,190	31,691	33,643
Earnings per share – basic:
From continuing operations (in dollars per share)									$ 1.53	$ 0.94	$ 0.16
From discontinued operations (in dollars per share)									0.00	1.95	0.16
Earnings per share – basic (in dollars per share)	$ 0.43	$ 0.49	$ 0.41	$ 0.20	$ 0.30	$ 2.07	$ 0.33	$ 0.19	1.53	2.89	0.32
Earnings per share – diluted:
From continuing operations (in dollars per share)									1.52	0.93	0.16
From discontinued operations (in dollars per share)									0.00	1.94	0.16
Earnings per share – diluted (in dollars per share)	$ 0.43	$ 0.48	$ 0.41	$ 0.20	$ 0.30	$ 2.06	$ 0.33	$ 0.19	$ 1.52	$ 2.87	$ 0.32