Pension and Other Post-Retirement Benefits - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($)
Funded Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit payment amount	$ 22.4
Unfunded Pension Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit payment amount	1.9
Anticipated future payments	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	0.3
Anticipated future payments	$ 0.5