Securities - Summary of debt securities available-for-sale in unrealized loss position (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	$ 269,439	$ 281,051
Unrealized Loss, Less than 12 Months	713	1,418
Fair Value, 12 Months or More	59,054	96,663
Unrealized Loss, 12 Months or More	1,584	1,590
Fair Value, Total	328,493	377,714
Unrealized Loss, Total	2,297	3,008
U.S. Government agencies
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	7,442	404
Unrealized Loss, Less than 12 Months	58	1
Fair Value, 12 Months or More	0	0
Unrealized Loss, 12 Months or More	0	0
Fair Value, Total	7,442	404
Unrealized Loss, Total	58	1
State and political subdivisions
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	6,182
Unrealized Loss, Less than 12 Months	13
Fair Value, 12 Months or More	0
Unrealized Loss, 12 Months or More	0
Fair Value, Total	6,182
Unrealized Loss, Total	13
Residential mortgage-backed securities, Agency
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	111,540	228,611
Unrealized Loss, Less than 12 Months	274	576
Fair Value, 12 Months or More	749	18,294
Unrealized Loss, 12 Months or More	2	150
Fair Value, Total	112,289	246,905
Unrealized Loss, Total	276	726
Commercial mortgage-backed, Agency
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	29,604	0
Unrealized Loss, Less than 12 Months	77	0
Fair Value, 12 Months or More	0	33,517
Unrealized Loss, 12 Months or More	0	128
Fair Value, Total	29,604	33,517
Unrealized Loss, Total	77	128
Commercial mortgage-backed, Non-agency
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months		0
Unrealized Loss, Less than 12 Months		0
Fair Value, 12 Months or More		4,864
Unrealized Loss, 12 Months or More		263
Fair Value, Total		4,864
Unrealized Loss, Total		263
Corporate bonds
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	4,653	19,742
Unrealized Loss, Less than 12 Months	25	216
Fair Value, 12 Months or More	0	998
Unrealized Loss, 12 Months or More	0	2
Fair Value, Total	4,653	20,740
Unrealized Loss, Total	25	218
Asset-backed securities
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	110,018	32,294
Unrealized Loss, Less than 12 Months	266	625
Fair Value, 12 Months or More	58,305	38,990
Unrealized Loss, 12 Months or More	1,582	1,047
Fair Value, Total	168,323	71,284
Unrealized Loss, Total	$ 1,848	$ 1,672