Pension and Other Post-Retirement Benefits - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Funded Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated additional payments in 2013	$ 22.0
Unfunded Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit payment amount	1.2
Estimated additional payments in 2013	3.2
Other Postretirement Benefit Plans Defined Benefit [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit payment amount	0.1
Estimated additional payments in 2013	$ 0.9