Retirement Benefits (Additional Information) (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling, general and administrative expenses	$ 130,473	$ 119,990
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	600
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year			$ 5,800
Expected contributions in current fiscal year	5,800
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year			$ 100
Expected contributions in current fiscal year	100
Accounting Standards Update 2017-17 | Other (Income) Expense Net
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling, general and administrative expenses	$ 800