Fair Value of Financial Instruments - Summary of Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets
Cash and due from banks	$ 120,954	$ 593,508
Interest–earning time deposits	4,046	4,782
Investment securities, held to maturity	2,006,129	1,552,443
Loans held for sale	3,781	12,579
Loans (excluding loan level hedges), net	3,659,209	3,590,331
Stock in FHLB	24,242	24,440
Interest receivable	27,476	26,137
Liabilities
Non–interest bearing deposits	1,325,570	1,360,338
Interest bearing deposits	4,525,927	4,442,653
Subordinated notes	58,786	58,750
Interest payable	1,420	2,235
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash and due from banks	120,954	593,508
Interest–earning time deposits	0	0
Investment securities, held to maturity	0	0
Loans held for sale	0	0
Loans (excluding loan level hedges), net	0	0
Stock in FHLB	0	0
Interest receivable	0	0
Mortgage servicing rights	0	0
Liabilities
Non–interest bearing deposits	1,325,570	1,360,338
Interest bearing deposits	0	0
Borrowings	0	0
Subordinated notes	0	0
Junior subordinated debentures issued to capital trusts	0	0
Interest payable	0	0
Significant Other Observable Inputs (Level 2)
Assets
Cash and due from banks	0	0
Interest–earning time deposits	4,072	4,861
Investment securities, held to maturity	1,827,845	1,513,520
Loans held for sale	0	0
Loans (excluding loan level hedges), net	0	0
Stock in FHLB	24,242	24,440
Interest receivable	27,476	26,137
Mortgage servicing rights	0	0
Liabilities
Non–interest bearing deposits	0	0
Interest bearing deposits	4,383,489	4,369,011
Borrowings	717,843	708,275
Subordinated notes	55,551	57,906
Junior subordinated debentures issued to capital trusts	52,692	53,420
Interest payable	1,420	2,235
Significant Unobservable Inputs (Level 3)
Assets
Cash and due from banks	0	0
Interest–earning time deposits	0	0
Investment securities, held to maturity	0	46,471
Loans held for sale	3,781	12,579
Loans (excluding loan level hedges), net	3,505,472	3,479,958
Stock in FHLB	0	0
Interest receivable	0	0
Mortgage servicing rights	18,592	15,186
Liabilities
Non–interest bearing deposits	0	0
Interest bearing deposits	0	0
Borrowings	0	0
Subordinated notes	0	0
Junior subordinated debentures issued to capital trusts	0	0
Interest payable	0	0
Carrying Amount
Assets
Cash and due from banks	120,954	593,508
Interest–earning time deposits	4,046	4,782
Investment securities, held to maturity	2,006,129	1,552,443
Loans held for sale	3,781	12,579
Loans (excluding loan level hedges), net	3,659,209	3,590,331
Stock in FHLB	24,242	24,440
Interest receivable	27,476	26,137
Mortgage servicing rights	18,592	15,186
Liabilities
Non–interest bearing deposits	1,325,570	1,360,338
Interest bearing deposits	4,525,927	4,442,653
Borrowings	728,664	712,739
Subordinated notes	58,786	58,750
Junior subordinated debentures issued to capital trusts	56,850	56,785
Interest payable	$ 1,420	$ 2,235