Commitments and Contingent Liabilities - Summary of Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Commitments to Grant Loans
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Commitments to grant loans	$ 44,712	$ 292,199
Standby Letters of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Letters of credit	216,267	213,548
Performance Letters of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Performance letters of credit	23,565	27,985
Commercial Letters of Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Letters of credit	20,126	15,587
Commitments to Extend Credit
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Commitments to extend credit	$ 3,985,508	$ 4,667,360