Benefit Plans - Assumptions Used to Determine Pension Expense (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Discount rate - projected benefit obligation	4.30%	3.69%	4.12%
Discount rate - interest cost	3.99%	3.31%	3.61%
Expected long-term return on plan assets	7.50%	7.50%	7.50%