Employee Benefit Plans - Changes in Benefit Obligation (Detail) - Pension Benefits [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in benefit obligation
Benefit obligation at beginning of year	$ 2,199,356	$ 2,352,094
Service cost	7,746	8,562	$ 7,824
Interest cost	104,485	98,088	102,465
Plan participants’ contributions	2,585	2,838
Actuarial loss (gain)	139,851	(139,573)
Foreign currency exchange rate changes	5,449	(35,082)
Gross benefits paid	(154,676)	(87,571)
Plan amendments	2,063	0
Benefit obligation at end of year	$ 2,306,859	$ 2,199,356	$ 2,352,094