Securities - Schedule of Unrealized Loss and Fair Value on Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Fair Value
Less Than 12 Months	$ 332,099		$ 312,988
12 Months or Longer	73,338		214,951
Total	405,437		527,939
Unrealized Losses
Less Than 12 Months	(1,530)		(2,041)
12 Months or Longer	(568)		(2,506)
Total	(2,098)		(4,547)
U.S. Treasury securities and obligations of U.S. government agencies
Fair Value
Less Than 12 Months	0		758
12 Months or Longer	256		0
Total	256		758
Unrealized Losses
Less Than 12 Months	0		(4)
12 Months or Longer	(1)		0
Total	(1)		(4)
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities
Fair Value
Less Than 12 Months	203,405		220,057
12 Months or Longer	569		104,184
Total	203,974		324,241
Unrealized Losses
Less Than 12 Months	(1,218)		(1,461)
12 Months or Longer	(22)		(1,923)
Total	(1,240)		(3,384)
Private mortgage-backed securities and collateralized mortgage obligations
Fair Value
Less Than 12 Months	23,997		2,978
12 Months or Longer	0		0
Total	23,997		2,978
Unrealized Losses
Less Than 12 Months	(210)		(5)
12 Months or Longer	0		0
Total	(210)		(5)
Collateralized loan obligations
Fair Value
Less Than 12 Months	104,697		88,680
12 Months or Longer	72,513		110,767
Total	177,210		199,447
Unrealized Losses
Less Than 12 Months	(102)		(570)
12 Months or Longer	(545)		(583)
Total	$ (647)	$ (1,200)	(1,153)
Obligations of state and political subdivisions
Fair Value
Less Than 12 Months			515
12 Months or Longer			0
Total			515
Unrealized Losses
Less Than 12 Months			(1)
12 Months or Longer			0
Total			$ (1)