Securities - Summary of debt securities available-for-sale in unrealized loss position (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	$ 323,118	$ 281,051
Unrealized Loss, Less than 12 Months	5,581	1,418
Fair Value, 12 Months or More	60,878	96,663
Unrealized Loss, 12 Months or More	4,548	1,590
Fair Value, Total	383,996	377,714
Unrealized Loss, Total	10,129	3,008
State and political subdivisions
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	15,009
Unrealized Loss, Less than 12 Months	17
Fair Value, 12 Months or More	0
Unrealized Loss, 12 Months or More	0
Fair Value, Total	15,009
Unrealized Loss, Total	17
U.S. Government agencies
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months		404
Unrealized Loss, Less than 12 Months		1
Fair Value, 12 Months or More		0
Unrealized Loss, 12 Months or More		0
Fair Value, Total		404
Unrealized Loss, Total		1
Residential mortgage-backed securities, Agency
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	32,736	228,611
Unrealized Loss, Less than 12 Months	454	576
Fair Value, 12 Months or More	1,856	18,294
Unrealized Loss, 12 Months or More	5	150
Fair Value, Total	34,592	246,905
Unrealized Loss, Total	459	726
Residential mortgage-backed securities, Non-agency
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	151,965
Unrealized Loss, Less than 12 Months	2,891
Fair Value, 12 Months or More	0
Unrealized Loss, 12 Months or More	0
Fair Value, Total	151,965
Unrealized Loss, Total	2,891
Commercial mortgage-backed, Agency
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	8,655	0
Unrealized Loss, Less than 12 Months	29	0
Fair Value, 12 Months or More	0	33,517
Unrealized Loss, 12 Months or More	0	128
Fair Value, Total	8,655	33,517
Unrealized Loss, Total	29	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	94,040	19,742
Unrealized Loss, Less than 12 Months	950	216
Fair Value, 12 Months or More	0	998
Unrealized Loss, 12 Months or More	0	2
Fair Value, Total	94,040	20,740
Unrealized Loss, Total	950	218
Asset-backed securities
Summary of available for sale securities in an unrealized loss position
Fair Value, Less than 12 Months	20,713	32,294
Unrealized Loss, Less than 12 Months	1,240	625
Fair Value, 12 Months or More	59,022	38,990
Unrealized Loss, 12 Months or More	4,543	1,047
Fair Value, Total	79,735	71,284
Unrealized Loss, Total	$ 5,783	$ 1,672