Employee Benefit Plans (Detail) - Pension Plan Cost and Obligations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Accumulated benefit obligation	$ 67,185	$ 67,283
Change in projected benefit obligation:
Projected benefit obligation at the beginning of the year	67,283	61,292
Service cost	0	0	$ 2,600
Interest cost	2,334	2,346	2,414
Settlements	(7,320)	(6,502)
Actuarial loss	5,336	10,508
Benefits paid	(448)	(361)
Projected benefit obligation at the end of the year	67,185	67,283	61,292
Change in fair value of plan assets:
Fair value of plan assets at the beginning of the year	72,193	74,370
Actual return on plan assets	478	4,686
Benefits paid	(448)	(361)
Settlements	(7,320)	(6,502)
Fair value of plan assets at the end of the year	64,903	72,193	$ 74,370
Funded status recognized in the Consolidated Statements of Financial Condition:
Noncurrent (liability) asset	(2,282)	4,910
Amounts recognized in accumulated other comprehensive loss:
Prior service cost	0	0
Net loss	26,481	19,911
Net amount recognized	$ 26,481	$ 19,911
Actuarial losses included in accumulated other comprehensive loss as a percent of:
Accumulated benefit obligation	39.40%	29.60%
Fair value of plan assets	40.80%	27.60%
Amounts expected to be amortized from accumulated other comprehensive loss into net periodic benefit cost in the next fiscal year:
Prior service cost	$ 0	$ 0
Net loss	516	401
Net amount expected to be recognized	$ 516	$ 401
Weighted-average assumptions at the end of the year used to determine the actuarial present value of the projected benefit obligation:
Discount rate	3.99%	3.60%