Accumulated Other Comprehensive Loss - Summary of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 109,770
Ending Balance	125,347
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(2,289)	$ (4,583)
Other comprehensive income (loss) before reclassifications	(1,193)	2,303
Amounts reclassified from accumulated other comprehensive loss	0	0
Ending Balance	$ (3,482)	$ (2,280)