Pension, Profit Sharing, and Other Employee Benefit Plans (Plan's funded status) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected obligation at January 1	$ 42,629	$ 33,559
Interest cost	1,629	1,600	$ 1,550
Actuarial loss (gain)	(212)	367
Benefit payments	(1,971)	(1,406)
Increase (decrease) related to discount rate change	(2,659)	8,509
Projected obligation at December 31	39,416	42,629	33,559
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at January 1	33,200	33,244
Actual return on plan assets	(546)	1,362
Benefit payments	(1,971)	(1,406)
Fair value of plan assets at December 31	30,683	33,200	33,244
Funded status at December 31	(8,733)	(9,429)
Accumulated benefit obligation at December 31	39,416	42,629
Unrecognized net actuarial loss	13,038	14,774	5,539
Net periodic pension cost not yet recognized	$ 13,038	$ 14,774	$ 5,539