Commitments and Contingent Liabilities - Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial instruments with off-balance sheet risk
Contract amount	$ 6,700,000	$ 6,700,000
Commitments to extend credit
Financial instruments with off-balance sheet risk
Contract amount	6,546,389	6,490,301
Standby letters of credit
Financial instruments with off-balance sheet risk
Contract amount	182,423	182,447
Commercial letters of credit
Financial instruments with off-balance sheet risk
Contract amount	$ 7,149	$ 3,307