Summary of Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Income (loss) from continuing operations	$ 9,061	$ 7,995	$ 7,953	$ 4,389	$ (9,714)	$ 7,636	$ 5,443	$ 1,929	$ 29,398	$ 5,294	$ (42,131)
Income from discontinued operations, net of tax	(116)	57,023	2,750	1,860	1,480	1,343	1,505	1,165	61,517	5,493	28,428
Net income (loss)	$ 8,945	$ 65,018	$ 10,703	$ 6,249	$ (8,234)	$ 8,979	$ 6,948	$ 3,094	$ 90,915	$ 10,787	$ (13,703)
Denominator:
Weighted average shares outstanding – basic									31,475	33,511	35,791
Common stock equivalents									216	132	0
Weighted average shares outstanding – diluted									31,691	33,643	35,791
Earnings (loss) per share – basic:
From continuing operations									$ 0.94	$ 0.16	$ (1.18)
From discontinued operations									$ 1.95	$ 0.16	$ 0.80
Earnings (loss) per share - basic	$ 0.30	$ 2.07	$ 0.33	$ 0.19	$ (0.25)	$ 0.27	$ 0.21	$ 0.09	$ 2.89	$ 0.32	$ (0.38)
Earnings (loss) per share - diluted:
From continuing operations									$ 0.93	$ 0.16	$ (1.18)
From discontinued operations									$ 1.94	$ 0.16	$ 0.80
Earnings (loss) per share - diluted	$ 0.30	$ 2.06	$ 0.33	$ 0.19	$ (0.25)	$ 0.27	$ 0.21	$ 0.09	$ 2.87	$ 0.32	$ (0.38)