Securities - Investment Category and Length of Time in Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2020 USD ($) security	Dec. 31, 2019 USD ($) security
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	21	79
Fair Value, Less than 12 Months	$ 75,359	$ 331,023
Unrealized Losses, Less than 12 Months	$ (211)	$ (2,394)
Number of positions, 12 Months or More \| security	4	22
Fair Value, 12 Months or More	$ 10,037	$ 33,700
Unrealized Losses, 12 Months or More	$ (3,004)	$ (2,484)
Number of positions \| security	25	101
Fair Value	$ 85,396	$ 364,723
Unrealized Losses	$ (3,215)	$ (4,878)
Obligations of other U.S. Government agencies and corporations
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security		0
Fair Value, Less than 12 Months		$ 0
Unrealized Losses, Less than 12 Months		$ 0
Number of positions, 12 Months or More \| security		1
Fair Value, 12 Months or More		$ 1,008
Unrealized Losses, 12 Months or More		$ (3)
Number of positions \| security		1
Fair Value		$ 1,008
Unrealized Losses		$ (3)
Obligations of states and political subdivisions
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	6	26
Fair Value, Less than 12 Months	$ 9,403	$ 33,902
Unrealized Losses, Less than 12 Months	$ (45)	$ (365)
Number of positions, 12 Months or More \| security	0	0
Fair Value, 12 Months or More	$ 0	$ 0
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of positions \| security	6	26
Fair Value	$ 9,403	$ 33,902
Unrealized Losses	$ (45)	$ (365)
Trust preferred securities
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	0	0
Fair Value, Less than 12 Months	$ 0	$ 0
Unrealized Losses, Less than 12 Months	$ 0	$ 0
Number of positions, 12 Months or More \| security	2	2
Fair Value, 12 Months or More	$ 9,012	$ 9,986
Unrealized Losses, 12 Months or More	$ (3,001)	$ (2,167)
Number of positions \| security	2	2
Fair Value	$ 9,012	$ 9,986
Unrealized Losses	$ (3,001)	$ (2,167)
Other debt securities
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	4	3
Fair Value, Less than 12 Months	$ 3,330	$ 8,737
Unrealized Losses, Less than 12 Months	$ (70)	$ (131)
Number of positions, 12 Months or More \| security	1	1
Fair Value, 12 Months or More	$ 566	$ 741
Unrealized Losses, 12 Months or More	$ (3)	$ (1)
Number of positions \| security	5	4
Fair Value	$ 3,896	$ 9,478
Unrealized Losses	$ (73)	$ (132)
Government agency mortgage backed securities \| Residential mortgage backed securities
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	2	37
Fair Value, Less than 12 Months	$ 19,755	$ 233,179
Unrealized Losses, Less than 12 Months	$ (23)	$ (1,504)
Number of positions, 12 Months or More \| security	0	16
Fair Value, 12 Months or More	$ 0	$ 20,775
Unrealized Losses, 12 Months or More	$ 0	$ (312)
Number of positions \| security	2	53
Fair Value	$ 19,755	$ 253,954
Unrealized Losses	$ (23)	$ (1,816)
Government agency mortgage backed securities \| Commercial mortgage backed securities
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	1	1
Fair Value, Less than 12 Months	$ 1,538	$ 4,976
Unrealized Losses, Less than 12 Months	$ (1)	$ (23)
Number of positions, 12 Months or More \| security	1	2
Fair Value, 12 Months or More	$ 459	$ 1,190
Unrealized Losses, 12 Months or More	$ 0	$ (1)
Number of positions \| security	2	3
Fair Value	$ 1,997	$ 6,166
Unrealized Losses	$ (1)	$ (24)
Government agency collateralized mortgage obligations \| Residential mortgage backed securities
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	5	11
Fair Value, Less than 12 Months	$ 27,143	$ 45,319
Unrealized Losses, Less than 12 Months	$ (51)	$ (262)
Number of positions, 12 Months or More \| security	0	0
Fair Value, 12 Months or More	$ 0	$ 0
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of positions \| security	5	11
Fair Value	$ 27,143	$ 45,319
Unrealized Losses	$ (51)	$ (262)
Government agency collateralized mortgage obligations \| Commercial mortgage backed securities
Unrealized losses and fair value by investment category
Number of positions, Less than 12 Months \| security	3	1
Fair Value, Less than 12 Months	$ 14,190	$ 4,910
Unrealized Losses, Less than 12 Months	$ (21)	$ (109)
Number of positions, 12 Months or More \| security	0	0
Fair Value, 12 Months or More	$ 0	$ 0
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of positions \| security	3	1
Fair Value	$ 14,190	$ 4,910
Unrealized Losses	$ (21)	$ (109)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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