Securities - Carrying Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Amortized Cost
Within one year	$ 0
One to five years	31,197
Five to ten years	82,255
After ten years	87,326
Amortized Cost	200,778
Amortized cost	528,052	$ 546,640
Held-to-maturity securities, One to five years	2,869
Held-to-maturity securities, Five to ten years	53,181
Held-to-maturity securities, After ten years	12,204
Held-to-maturity securities, Amortized Cost	68,254
Fair Value
Within one year	0
One to five years	26,893
Five to ten years	80,704
After ten years	89,875
Fair Value	197,472
Fair Value	528,311	540,852
Held-to-maturity securities, One to five years	2,989
Held-to-maturity securities, Five to ten years	53,544
Held-to-maturity securities, After ten years	12,643
Held-to-maturity securities, Fair Value	69,176
Agency mortgage-backed securities
Amortized Cost
Amortized cost	250,755	264,142
Fair Value
Fair Value	253,292	261,440
Private label mortgage-backed securities
Amortized Cost
Amortized cost	71,519	63,704
Fair Value
Fair Value	72,626	63,613
Asset-backed securities
Amortized Cost
Amortized cost	5,000	5,000
Fair Value
Fair Value	$ 4,921	$ 4,955