Commitments and Contingencies - Schedule of Commitments (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
---|---|---|
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
Total unfunded off-balance sheet credit risk | $ 1,364,114 | $ 737,572 |
Commitments to Extend Credit | ||
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
Total unfunded off-balance sheet credit risk | 1,342,271 | 737,572 |
Standby Letters of Credit | ||
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
Total unfunded off-balance sheet credit risk | 343 | 0 |
Purchase Commitment | ||
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
Total unfunded off-balance sheet credit risk | $ 21,500 | $ 0 |