Retirement Plans - Defined Benefit Plans - Detail of Prior Service Cost and Net Actuarial Loss Recognized In Accumulated Other Comprehensive Income (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Amounts recognized in Accumulated other comprehensive loss:    
Prior service cost $ 756 $ 1,923
Net actuarial loss $ 26,361 $ 9,512