Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Type (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Stock Based Compensation [Line Items]
Total	$ 668	$ 729
Continuing Operations [Member]
Stock Based Compensation [Line Items]
Total	668	708
Discontinued Operations [Member]
Stock Based Compensation [Line Items]
Total	0	21
Service-based awards [Member] | Continuing Operations [Member]
Stock Based Compensation [Line Items]
Total	572	624
Equity Awards for Short-term Incentive Plan [Member] | Continuing Operations [Member]
Stock Based Compensation [Line Items]
Total	41	0
Stock Option and Employee Purchase Plans [Member] | Continuing Operations [Member]
Stock Based Compensation [Line Items]
Total	$ 55	$ 84