Income Taxes Provision for Income Tax (Detail) - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Income Tax Disclosure [Abstract] | |||||
| Federal | $ 60,837 | $ 39,576 | $ 40,127 | ||
| State | 7,164 | 8,947 | 4,060 | ||
| Total current provision | 68,001 | 48,523 | 44,187 | ||
| Federal | (9,855) | 16,037 | (520) | ||
| State | (2,216) | (1,202) | 290 | ||
| Total deferred (benefit) provision | (12,071) | 14,835 | (230) | ||
| Total provision | $ 22,506 | $ 18,406 | $ 55,930 | $ 63,358 | $ 43,957 |