Fair Value Measurements - Carrying Values and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Securities	$ 773,693		$ 784,283
Loans held for sale	18,528		5,256
Portfolio loans, net	7,108,248	$ 7,074,928	7,074,928
FHLB and other restricted stock	13,030		22,977
LIABILITIES
Junior subordinated debt securities	64,083		64,277	$ 45,619
Carrying Value
ASSETS
Cash and due from banks, including interest-bearing deposits	229,666		197,823
Securities	773,693		784,283
Loans held for sale	18,528		5,256
Portfolio loans, net	7,108,248		7,074,928
Bank owned life insurance	82,303		80,473
FHLB and other restricted stock	13,030		22,977
Collateral receivable	77,936
Securities held in a deferred compensation plan	6,794		5,987
Mortgage servicing rights	4,976		4,662
LIABILITIES
Deposits	7,420,538		7,036,576
Securities sold under repurchase agreements	65,163		19,888
Short-term borrowings	75,000		281,319
Long-term borrowings	23,681		50,868
Junior subordinated debt securities	64,083		64,277
Carrying Value | Interest rate swaps
ASSETS
Derivative financial assets	78,319		25,647
LIABILITIES
Derivative financial liabilities	79,033		25,615
Carrying Value | Interest rate lock commitments
ASSETS
Derivative financial assets	2,900		321
Carrying Value | Forward sale contracts
ASSETS
Derivative financial assets			1
LIABILITIES
Derivative financial liabilities	385
Fair Value Measurements
ASSETS
Cash and due from banks, including interest-bearing deposits	229,666		197,823
Securities	773,693		784,283
Loans held for sale	18,528		5,256
Portfolio loans, net	7,028,446		6,940,875
Bank owned life insurance	82,303		80,473
FHLB and other restricted stock	13,030		22,977
Collateral receivable	77,936
Securities held in a deferred compensation plan	6,794		5,987
Mortgage servicing rights	4,976		4,650
LIABILITIES
Deposits	7,422,894		7,034,595
Securities sold under repurchase agreements	65,163		19,888
Short-term borrowings	75,000		281,319
Long-term borrowings	24,545		51,339
Junior subordinated debt securities	64,083		64,277
Fair Value Measurements | Interest rate swaps
ASSETS
Derivative financial assets	78,319		25,647
LIABILITIES
Derivative financial liabilities	79,033		25,615
Fair Value Measurements | Interest rate lock commitments
ASSETS
Derivative financial assets	2,900		321
Fair Value Measurements | Forward sale contracts
ASSETS
Derivative financial assets			1
LIABILITIES
Derivative financial liabilities	385
Fair Value Measurements | Level 1
ASSETS
Cash and due from banks, including interest-bearing deposits	229,666		197,823
Securities	3,228		5,078
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	77,936
Securities held in a deferred compensation plan	6,794		5,987
Mortgage servicing rights	0		0
LIABILITIES
Deposits	6,033,075		5,441,143
Securities sold under repurchase agreements	65,163		19,888
Short-term borrowings	75,000		281,319
Long-term borrowings	4,494		4,678
Junior subordinated debt securities	64,083		64,277
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	770,465		779,205
Loans held for sale	0		0
Portfolio loans, net	0		0
Bank owned life insurance	82,303		80,473
FHLB and other restricted stock	0		0
Collateral receivable	0
Securities held in a deferred compensation plan	0		0
Mortgage servicing rights	0		0
LIABILITIES
Deposits	1,389,819		1,593,452
Securities sold under repurchase agreements	0		0
Short-term borrowings	0		0
Long-term borrowings	20,051		46,661
Junior subordinated debt securities	0		0
Fair Value Measurements | Level 2 | Interest rate swaps
ASSETS
Derivative financial assets	78,319		25,647
LIABILITIES
Derivative financial liabilities	79,033		25,615
Fair Value Measurements | Level 2 | Interest rate lock commitments
ASSETS
Derivative financial assets	0		321
Fair Value Measurements | Level 2 | Forward sale contracts
ASSETS
Derivative financial assets			1
LIABILITIES
Derivative financial liabilities	385
Fair Value Measurements | Level 3
ASSETS
Cash and due from banks, including interest-bearing deposits	0		0
Securities	0		0
Loans held for sale	18,528		5,256
Portfolio loans, net	7,028,446		6,940,875
Bank owned life insurance	0		0
FHLB and other restricted stock	13,030		22,977
Collateral receivable	0
Securities held in a deferred compensation plan	0		0
Mortgage servicing rights	4,976		4,650
LIABILITIES
Deposits	0		0
Securities sold under repurchase agreements	0		0
Short-term borrowings	0		0
Long-term borrowings	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	2,900		0
Fair Value Measurements | Level 3 | Forward sale contracts
ASSETS
Derivative financial assets			$ 0
LIABILITIES
Derivative financial liabilities	$ 0