Defined Contribution Plans, Pension and Other Post-Retirement Benefit Plans - Expected Future Benefit Payments of Pension and Other Post-Retirement Benefit Plans (Detail) - Pension Plans, Defined Benefit $ in Thousands	Dec. 31, 2016 USD ($)
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
2017	$ 3,698
2018	3,902
2019	4,095
2020	4,279
2021	4,326
2022 to 2026	$ 22,372

Defined Contribution Plans, Pension and Other Post-Retirement Benefit Plans - Expected Future Benefit Payments of Pension and Other Post-Retirement Benefit Plans (Detail) - Pension Plans, Defined Benefit
$ in Thousands

Dec. 31, 2016

USD ($)

Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]

$ 3,698

3,902

4,095

4,279

4,326

$ 22,372