Benefit Plans - Component of Net Periodic Pension Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Net actuarial loss	$ 36,271	$ 43,091
Deferred tax benefit	(15,118)	(18,031)
Total	$ 21,153	$ 25,060