Employee Benefit Plans (Net Periodic Cost) (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| Compensation And Retirement Disclosure [Abstract] | ||
| Service costs | $ 261 | $ 390 |
| Interest costs | 5,964 | 7,009 |
| Expected return on plan assets | (3,094) | (5,448) |
| Amortization of net actuarial loss | 7,037 | 8,492 |
| Amortization of prior service credit | (1,211) | (1,041) |
| Net periodic cost | $ 8,957 | $ 9,402 |