Pensions and Other Post-retirement Benefits - Schedule of Expected Return on Assets for Net Periodic Pension Cost (Detail)	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Total	100.00%	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Total	70.00%	67.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total	20.00%	24.00%
Pooled investment funds
Defined Benefit Plan Disclosure [Line Items]
Total	5.00%	5.00%
Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total	4.00%	3.00%
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total	1.00%	1.00%