Pension and Other Postretirement Benefits - Schedule of Weighted Average Assumptions Used to Determine Benefit Obligations (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Discount rate	4.20%	4.29%
Rate of compensation increase	3.50%	3.50%	3.50%
Discount rate	4.29%	4.00%	4.80%
Expected long-term rate of return on plan assets	7.75%	7.75%	8.00%
Rate of compensation increase	3.50%	3.50%	3.50%