Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			$ 321,673	$ 509,457
Other comprehensive income	$ 48	$ 591	136	850
Ending Balance	589,333	466,106	589,333	466,106
Unrealized Gains and (Losses) on Securities Available-for- Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(224)	(465)
Other comprehensive income (loss), before reclassifications			134	281
Amounts reclassified from accumulated other comprehensive income			0	0
Other comprehensive income			134	281
Ending Balance	(90)	(184)	(90)	(184)
Other comprehensive income (loss), before reclassifications, tax			(83)	(171)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			0	(569)
Other comprehensive income (loss), before reclassifications			0	569
Amounts reclassified from accumulated other comprehensive income			0	0
Other comprehensive income			0	569
Ending Balance	$ 0	$ 0	$ 0	0
Other comprehensive income (loss), before reclassifications, tax				$ (348)