Fair Value Measurements - Book Value and Estimated Fair Value of Bank's Significant Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financial Assets:
Debt securities held-to-maturity	$ 987,532	$ 1,152,744
Restricted equity investments	76,047	53,195
Financial Liabilities:
Time deposits	1,499,975	775,001
Securities sold under agreements to repurchase with customers	105,495	118,769
Book Value
Financial Assets:
Cash and due from banks	189,019	204,949
Debt securities held-to-maturity	1,068,034	1,139,193
Restricted equity investments	76,047	53,195
Loans receivable, net and loans held-for-sale	9,380,688	8,583,352
Financial Liabilities:
Deposits other than time deposits	8,331,509	8,957,815
Time deposits	1,499,975	775,001
FHLB advances and other borrowings	683,404	229,141
Securities sold under agreements to repurchase with customers	105,495	118,769
Level 1 Inputs
Financial Assets:
Cash and due from banks	189,019	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	105,495	118,769
Level 2 Inputs
Financial Assets:
Cash and due from banks	0	0
Debt securities held-to-maturity	975,027	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	8,331,509	8,957,815
Time deposits	1,472,791	773,766
FHLB advances and other borrowings	697,444	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	12,505	14,215
Restricted equity investments	76,047	53,195
Loans receivable, net and loans held-for-sale	9,013,653	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