Fair Value Measurements - Carrying Values and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
ASSETS
Securities, at fair value	$ 817,299	$ 773,693
Portfolio loans, net	7,068,067	7,108,248
FHLB and other restricted stock	12,199	13,030
LIABILITIES
Junior subordinated debt securities	64,097	64,083
Carrying Value
ASSETS
Cash and due from banks, including interest-bearing deposits	671,429	229,666
Securities, at fair value	817,299	773,693
Loans held for sale	12,794	18,528
Portfolio loans, net	7,068,067	7,108,248
Bank owned life insurance	82,677	82,303
FHLB and other restricted stock	12,199	13,030
Collateral receivable	43,343	77,936
Securities held in a deferred compensation plan	7,178	6,794
Mortgage servicing rights	6,590	4,976
LIABILITIES
Deposits	7,876,028	7,420,538
Securities sold under repurchase agreements	67,417	65,163
Short-term borrowings	0	75,000
Long-term borrowings	23,282	23,681
Junior subordinated debt securities	64,097	64,083
Carrying Value | Interest rate swaps
ASSETS
Derivative financial assets	40,415	78,319
LIABILITIES
Derivative financial liabilities	40,818	79,033
Carrying Value | Interest rate lock commitments
ASSETS
Derivative financial assets	1,509	2,900
Carrying Value | Forward sale contracts
ASSETS
Derivative financial assets	226
LIABILITIES
Derivative financial liabilities		385
Fair Value Measurements
ASSETS
Cash and due from banks, including interest-bearing deposits	671,429	229,666
Securities, at fair value	817,299	773,693
Loans held for sale	12,794	18,528
Portfolio loans, net	6,976,120	7,028,446
Bank owned life insurance	82,677	82,303
FHLB and other restricted stock	12,199	13,030
Collateral receivable	43,343	77,936
Securities held in a deferred compensation plan	7,178	6,794
Mortgage servicing rights	6,590	4,976
LIABILITIES
Deposits	7,876,232	7,422,894
Securities sold under repurchase agreements	67,417	65,163
Short-term borrowings	0	75,000
Long-term borrowings	23,903	24,545
Junior subordinated debt securities	64,097	64,083
Fair Value Measurements | Interest rate swaps
ASSETS
Derivative financial assets	40,415	78,319
LIABILITIES
Derivative financial liabilities	40,818	79,033
Fair Value Measurements | Interest rate lock commitments
ASSETS
Derivative financial assets	1,509	2,900
Fair Value Measurements | Forward sale contracts
ASSETS
Derivative financial assets	226
LIABILITIES
Derivative financial liabilities		385
Fair Value Measurements | Level 1
ASSETS
Cash and due from banks, including interest-bearing deposits	671,429	229,666
Securities, at fair value	0	3,228
Loans held for sale	0	0
Portfolio loans, net	0	0
Bank owned life insurance	0	0
FHLB and other restricted stock	0	0
Collateral receivable	43,343	77,936
Securities held in a deferred compensation plan	7,178	6,794
Mortgage servicing rights	0	0
LIABILITIES
Deposits	6,555,603	6,033,075
Securities sold under repurchase agreements	67,417	65,163
Short-term borrowings	0	75,000
Long-term borrowings	4,447	4,494
Junior subordinated debt securities	64,097	64,083
Fair Value Measurements | Level 1 | Interest rate swaps
ASSETS
Derivative financial assets	0	0
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements | Level 1 | Interest rate lock commitments
ASSETS
Derivative financial assets	0	0
Fair Value Measurements | Level 1 | Forward sale contracts
ASSETS
Derivative financial assets	0
LIABILITIES
Derivative financial liabilities		0
Fair Value Measurements | Level 2
ASSETS
Cash and due from banks, including interest-bearing deposits	0	0
Securities, at fair value	817,299	770,465
Loans held for sale	0	0
Portfolio loans, net	0	0
Bank owned life insurance	82,677	82,303
FHLB and other restricted stock	0	0
Collateral receivable	0	0
Securities held in a deferred compensation plan	0	0
Mortgage servicing rights	0	0
LIABILITIES
Deposits	1,320,629	1,389,819
Securities sold under repurchase agreements	0	0
Short-term borrowings	0	0
Long-term borrowings	19,456	20,051
Junior subordinated debt securities	0	0
Fair Value Measurements | Level 2 | Interest rate swaps
ASSETS
Derivative financial assets	40,415	78,319
LIABILITIES
Derivative financial liabilities	40,818	79,033
Fair Value Measurements | Level 2 | Interest rate lock commitments
ASSETS
Derivative financial assets	0	0
Fair Value Measurements | Level 2 | Forward sale contracts
ASSETS
Derivative financial assets	0
LIABILITIES
Derivative financial liabilities		385
Fair Value Measurements | Level 3
ASSETS
Cash and due from banks, including interest-bearing deposits	0	0
Securities, at fair value	0	0
Loans held for sale	12,794	18,528
Portfolio loans, net	6,976,120	7,028,446
Bank owned life insurance	0	0
FHLB and other restricted stock	12,199	13,030
Collateral receivable	0	0
Securities held in a deferred compensation plan	0	0
Mortgage servicing rights	6,590	4,976
LIABILITIES
Deposits	0	0
Securities sold under repurchase agreements	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Junior subordinated debt securities	0	0
Fair Value Measurements | Level 3 | Interest rate swaps
ASSETS
Derivative financial assets	0	0
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements | Level 3 | Interest rate lock commitments
ASSETS
Derivative financial assets	1,509	2,900
Fair Value Measurements | Level 3 | Forward sale contracts
ASSETS
Derivative financial assets	$ 226
LIABILITIES
Derivative financial liabilities		$ 0