Schedule of Reconciliation of Defined Benefit Pension Plan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
Fair value of plan assets at beginning of year	$ 116,697	$ 106,469
Actual return (loss) on plan assets	(3,223)	16,470
Benefits paid	(6,086)	(5,605)
Administrative expenses	(549)	(637)
Fair value of plan assets at end of year	106,839	116,697	$ 106,469
Benefit obligation at beginning of year	127,342	103,558
Service cost	1,051	966	1,060
Interest cost	4,912	4,986
Actuarial (gain) loss	(9,039)	23,437
Benefit obligation at end of year	118,180	127,342	$ 103,558
Other non-current liabilities	11,341	10,645
Total amounts recognized at end of year	$ 11,341	$ 10,645