Employee Benefit Plans - Unfunded Post Retirement Benefits Plan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Sale Of Subsidiary [Abstract]
Benefit obligation at beginning of year	$ 2,744	$ 2,485	$ 2,224
Interest cost	90	102	84
Service cost	96	84	125
Actual claims	(109)	(108)	(167)
Plan amendment	0	0	(602)
Actuarial loss	245	181	821
Benefit obligation at end of year	$ 3,066	$ 2,744	$ 2,485