Accumulated Other Comprehensive Income ("AOCI") - Summary of Total Changes in AOCI by Component, Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 249,370
Other comprehensive loss before reclassifications:
Loss on foreign currency translation adjustment	$ (5,897)	$ (563)	(3,444)	$ (10,098)
Amounts reclassified from AOCI:
Amortization of defined benefit pension actuarial gain	108	116	294	299
Other comprehensive loss, net of tax	(5,789)	(447)	(3,150)	(9,799)
Ending Balance	259,663		259,663
Defined Benefit Pension Plan Activity [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(5,687)	(5,832)	(5,873)	(6,015)
Other comprehensive loss before reclassifications:
Loss on foreign currency translation adjustment	0	0	0	0
Amounts reclassified from AOCI:
Amortization of defined benefit pension actuarial gain	108	116	294	299
Other comprehensive loss, net of tax	108	116	294	299
Ending Balance	(5,579)	(5,716)	(5,579)	(5,716)
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(51,257)	(50,960)	(53,710)	(41,425)
Other comprehensive loss before reclassifications:
Loss on foreign currency translation adjustment	(5,897)	(563)	(3,444)	(10,098)
Amounts reclassified from AOCI:
Amortization of defined benefit pension actuarial gain	0	0	0	0
Other comprehensive loss, net of tax	(5,897)	(563)	(3,444)	(10,098)
Ending Balance	(57,154)	(51,523)	(57,154)	(51,523)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(56,944)	(56,792)	(59,583)	(47,440)
Amounts reclassified from AOCI:
Ending Balance	$ (62,733)	$ (57,239)	$ (62,733)	$ (57,239)