Fair Value Measurements - Carrying Values and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
ASSETS
Securities, at fair value		$ 799,532	$ 784,283
Portfolio loans, net		7,149,895	7,074,928
FHLB and other restricted stock		28,253	22,977
LIABILITIES
Junior subordinated debt securities		64,038	64,277
Carrying Value
ASSETS
Cash and due from banks, including interest-bearing deposits	[1]	187,684	197,823
Securities, at fair value	[1]	799,532	784,283
Loans held for sale	[1]	7,309	5,256
Portfolio loans, net	[1]	7,149,895	7,074,928
Bank owned life insurance	[1]	80,978	80,473
FHLB and other restricted stock	[1]	28,253	22,977
Securities held in a deferred compensation plan	[1]	4,782	5,987
Mortgage servicing rights	[1]	3,979	4,662
LIABILITIES
Deposits	[1]	7,057,879	7,036,576
Securities sold under repurchase agreements	[1]	69,644	19,888
Short-term borrowings	[1]	410,240	281,319
Long-term borrowings	[1]	50,180	50,868
Junior subordinated debt securities	[1]	64,038	64,277
Carrying Value | Interest rate swaps
ASSETS
Derivative financial assets	[1]	88,135	25,647
LIABILITIES
Derivative financial liabilities	[1]	87,989	25,615
Carrying Value | Interest rate lock commitments
ASSETS
Derivative financial assets	[1]	2,927	321
Carrying Value | Forward sale contracts
ASSETS
Derivative financial assets	[1]		1
LIABILITIES
Derivative financial liabilities	[1]	1,292
Fair Value Measurements
ASSETS
Cash and due from banks, including interest-bearing deposits		187,684	197,823
Securities, at fair value		799,532	784,283
Loans held for sale		7,309	5,256
Portfolio loans, net		7,090,570	6,940,875
Bank owned life insurance		80,798	80,473
FHLB and other restricted stock		28,253	22,977
Securities held in a deferred compensation plan		4,782	5,987
Mortgage servicing rights		3,982	4,650
LIABILITIES
Deposits		7,065,896	7,034,595
Securities sold under repurchase agreements		69,644	19,888
Short-term borrowings		410,240	281,319
Long-term borrowings		51,675	51,339
Junior subordinated debt securities		64,038	64,277
Fair Value Measurements | Interest rate swaps
ASSETS
Derivative financial assets		88,135	25,647
LIABILITIES
Derivative financial liabilities		87,989	25,615
Fair Value Measurements | Interest rate lock commitments
ASSETS
Derivative financial assets		2,927	321
Fair Value Measurements | Forward sale contracts
ASSETS
Derivative financial assets			1
LIABILITIES
Derivative financial liabilities		1,292
Fair Value Measurements | Level 1
ASSETS
Cash and due from banks, including interest-bearing deposits		187,684	197,823
Securities, at fair value		3,504	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
Securities held in a deferred compensation plan		4,782	5,987
Mortgage servicing rights		0	0
LIABILITIES
Deposits		5,469,826	5,441,143
Securities sold under repurchase agreements		69,644	19,888
Short-term borrowings		410,240	281,319
Long-term borrowings		4,630	4,678
Junior subordinated debt securities		64,038	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, at fair value			779,205
Loans held for sale		0	0
Portfolio loans, net		0	0
Bank owned life insurance		80,798	80,473
FHLB and other restricted stock		0	0
Securities held in a deferred compensation plan		0	0
Mortgage servicing rights		0	0
LIABILITIES
Deposits		1,596,070	1,593,452
Securities sold under repurchase agreements		0	0
Short-term borrowings		0	0
Long-term borrowings		47,045	46,661
Junior subordinated debt securities		0	0
Fair Value Measurements | Level 2 | Interest rate swaps
ASSETS
Derivative financial assets		88,135	25,647
LIABILITIES
Derivative financial liabilities		87,989	25,615
Fair Value Measurements | Level 2 | Interest rate lock commitments
ASSETS
Derivative financial assets		2,927	321
Fair Value Measurements | Level 2 | Forward sale contracts
ASSETS
Derivative financial assets			1
LIABILITIES
Derivative financial liabilities		1,292
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		7,309	5,256
Portfolio loans, net		7,090,570	6,940,875
Bank owned life insurance		0	0
FHLB and other restricted stock		28,253	22,977
Securities held in a deferred compensation plan		0	0
Mortgage servicing rights		3,982	4,650
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		0	0
Fair Value Measurements | Level 3 | Forward sale contracts
ASSETS
Derivative financial assets			$ 0
LIABILITIES
Derivative financial liabilities		$ 0

[1] As reported in the Consolidated Balance Sheets