Fair Value Measurements - Book Value and Estimated Fair Value of Bank's Significant Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financial Assets:
Debt securities held-to-maturity	$ 905,426	$ 1,152,744
Restricted equity investments	77,556	53,195
Financial Liabilities:
Time deposits	1,404,357	775,001
Securities sold under agreements to repurchase with customers	96,289	118,769
Level 1 Inputs
Financial Assets:
Cash and due from banks	170,668	204,949
Debt securities held-to-maturity	0	0
Restricted equity investments	0	0
Loans receivable, net and loans held-for-sale	0	0
Financial Liabilities:
Deposits other than time deposits	0	0
Time deposits	0	0
FHLB advances and other borrowings	0	0
Securities sold under agreements to repurchase with customers	96,289	118,769
Level 2 Inputs
Financial Assets:
Cash and due from banks	0	0
Debt securities held-to-maturity	893,044	1,138,529
Restricted equity investments	0	0
Loans receivable, net and loans held-for-sale	0	0
Financial Liabilities:
Deposits other than time deposits	8,555,112	8,957,815
Time deposits	1,365,574	773,766
FHLB advances and other borrowings	722,430	251,491
Securities sold under agreements to repurchase with customers	0	0
Level 3 Inputs
Financial Assets:
Cash and due from banks	0	0
Debt securities held-to-maturity	12,382	14,215
Restricted equity investments	77,556	53,195
Loans receivable, net and loans held-for-sale	8,992,317	8,533,506
Financial Liabilities:
Deposits other than time deposits	0	0
Time deposits	0	0
FHLB advances and other borrowings	0	0
Securities sold under agreements to repurchase with customers	0	0
Book Value
Financial Assets:
Cash and due from banks	170,668	204,949
Debt securities held-to-maturity	1,027,712	1,139,193
Restricted equity investments	77,556	53,195
Loans receivable, net and loans held-for-sale	9,676,037	8,583,352
Financial Liabilities:
Deposits other than time deposits	8,555,112	8,957,815
Time deposits	1,404,357	775,001
FHLB advances and other borrowings	709,114	229,141
Securities sold under agreements to repurchase with customers	$ 96,289	$ 118,769