Benefit Plans - Weighted Average Discount Rate (Detail)		6 Months Ended	12 Months Ended
		Jun. 30, 2013	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]		4.02%	4.89%
Expected long-term return on plan assets		7.50%	7.50%	7.50%		7.50%
Rate of compensation increase						2.75%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.26%		4.26%	[1]
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.87%		4.87%	[1]

[1] The discount rate for 2013 increased from 4.26 percent to 4.87 percent due to the plans’ freeze and re-measurement at June 30, 2013.