Fair Value - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Assets
Securities available-for-sale	$ 332,129,000	$ 102,252,000
Securities held-to-maturity	650,829,000	657,649,000
Federal Home Loan Bank, Federal Reserve Bank stock and other investments, at cost	32,513,000	32,504,000
Liabilities
Subordinated debt	39,274,000	39,925,000
Carrying Amounts
Assets
Cash and cash equivalents	876,585,000	1,306,216,000
Securities available-for-sale	332,129,000	102,252,000
Securities held-to-maturity	723,716,000	658,397,000
Loans (including loans held-for-sale), net	3,039,243,000	3,046,403,000
Federal Home Loan Bank, Federal Reserve Bank stock and other investments, at cost	32,513,000	32,504,000
Accrued interest receivable	11,679,000	10,781,000
I/O strips receivables	173,000	221,000
Liabilities
Time deposits	139,625,000	139,834,000
Other deposits	4,474,019,000	4,619,578,000
Subordinated debt	39,274,000	39,925,000
Accrued interest payable	423,000	477,000
Balance
Assets
Cash and cash equivalents	876,585,000	1,306,216,000
Securities available-for-sale	332,129,000	102,252,000
Securities held-to-maturity	650,829,000	657,649,000
Loans (including loans held-for-sale), net	2,947,286,000	3,063,925,000
Accrued interest receivable	11,679,000	10,781,000
I/O strips receivables	173,000	221,000
Liabilities
Time deposits	139,912,000	140,086,000
Other deposits	4,474,019,000	4,619,578,000
Subordinated debt	38,424,000	40,425,000
Accrued interest payable	423,000	477,000
Balance | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash and cash equivalents	876,585,000	1,306,216,000
Securities available-for-sale	250,126,000
Accrued interest receivable	587,000
Balance | Significant Other Observable Inputs (Level 2)
Assets
Securities available-for-sale	82,003,000	102,252,000
Securities held-to-maturity	650,829,000	657,649,000
Loans (including loans held-for-sale), net	2,281,000	2,367,000
Accrued interest receivable	1,724,000	1,719,000
I/O strips receivables	173,000	221,000
Liabilities
Time deposits	139,912,000	140,086,000
Other deposits	4,474,019,000	4,619,578,000
Subordinated debt	38,424,000	40,425,000
Accrued interest payable	423,000	477,000
Balance | Significant Unobservable Inputs (Level 3)
Assets
Loans (including loans held-for-sale), net	2,945,005,000	3,061,558,000
Accrued interest receivable	$ 9,368,000	$ 9,062,000