Employee Benefit Plans (Detail) - Net Periodic Benefit Pension Expense - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components of net periodic benefit cost:
Service cost	$ 0	$ 0	$ 2,600
Interest cost	2,334	2,346	2,414
Expected return on plan assets	(4,333)	(4,931)	(4,299)
Recognized net actuarial loss	367	249	1,453
Amortization of prior service cost	0	0	1
Recognized settlement loss	2,254	1,377	0
Net periodic cost (income)	622	(959)	2,169
Other changes in plan assets and benefit obligations recognized as a charge to other comprehensive (loss) income:
Net (loss) gain for the period	(9,191)	(10,752)	16,146
Amortization of prior service cost	0	0	1
Amortization of net loss	2,621	1,625	1,453
Total unrealized (loss) gain	(6,570)	(9,127)	17,600
Total recognized in net periodic pension cost and other comprehensive (loss) income	$ (7,192)	$ (8,168)	$ 15,431
Weighted-average assumptions used to determine the net periodic cost:
Discount rate	3.60%	4.30%	3.40%
Expected return on plan assets	6.50%	7.25%	7.25%
Rate of compensation increase			2.50%