Employee Benefit Plans - Status of Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefit Plan [Member]
Change in benefit obligation:
Beginning of year	$ 0	$ 2,016	$ 2,190
Service cost		0	0
Interest cost		36	87
Actuarial loss (gain)		(9)	35
Negative plan amendment benefit		0	0
Benefits paid		(2,043)	(296)
Benefit obligation at end of year		0	2,016
Post-Employment Benefit Plan [Member]
Change in benefit obligation:
Beginning of year	4,681	4,926	4,827
Service cost	36	51	72
Interest cost	142	141	149
Actuarial loss (gain)	(297)	45	1,632
Negative plan amendment benefit	0	0	(1,183)
Benefits paid	(456)	(482)	(571)
Benefit obligation at end of year	$ 4,106	$ 4,681	$ 4,926