Commitments and Contingencies - Summary of Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Total unfunded off-balance sheet credit risk	$ 1,859,981	$ 1,447,624
Commitments to Extend Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Total unfunded off-balance sheet credit risk	1,834,449	1,435,024
Standby Letters of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Total unfunded off-balance sheet credit risk	$ 25,532	2,150
Airplane Purchase Agreement Commitments
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Total unfunded off-balance sheet credit risk		$ 10,450