Employee Benefit Plans and Other Postretirement Plans - Additional Information (Detail) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss	$ (139,600,000)	$ (124,900,000)
Company contributions	57,100,000	57,100,000	$ 400,000
Deferred compensation liability	13,700,000	$ 12,800,000
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 8,000,000
Employee Stock Ownership Plan
Defined Benefit Plan Disclosure [Line Items]
Company's common stock		2.2
Minimum
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to pension plan, percentage	3.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to pension plan, percentage	5.00%
Matching Contributions
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to defined contribution plans	$ 40,400,000	$ 37,900,000	28,300,000
Service Related Contributions
Defined Benefit Plan Disclosure [Line Items]
Company's contribution to defined contribution plans	$ 14,900,000	12,400,000	7,400,000
Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Minimum retirement age for medical benefit plan coverage, years	58
Minimum service period for medical benefit plan coverage, years	10
Benefit obligation	$ 19,500,000	21,400,000	$ 31,900,000
Employee age after which minimum service period to be completed for medical benefit plan coverage, years	48
Company contributions	$ 1,400,000	$ 2,000,000
Postretirement Health Coverage | Adjustments
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation				$ (5,100,000)
Accumulated other comprehensive loss				3,100,000
Deferred income taxes				$ 2,000,000