Retirement Plans - Defined Benefit Plans - Summary of Expected Future Pension Benefit Payments (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Expected future pension benefit payments:  
2015 $ 2,607
2016 2,887
2017 3,196
2018 3,589
2019 4,048
2020-2024 $ 28,277