Comprehensive Income - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Comprehensive Income
Gain (loss) on sale of available-for-sale securities, net	$ 554		$ (50)		$ 830	$ (168)
Income from continuing operations, before income taxes	24,042		19,926		25,269	23,915
Income tax expense	(6,008)		(4,995)		(6,187)	(5,792)
Net income	18,034	$ 1,048	15,377	$ 3,192	19,082	18,569
Salaries and benefits	(22,659)		(13,280)		(38,841)	(25,014)
Interest on investment securities - taxable	477		768		1,143	1,647
Amount reclassified from AOCI
Comprehensive Income
Net income	(374)		(329)		1,060	(130)
Available-for-sale securities | Amount reclassified from AOCI
Comprehensive Income
Gain (loss) on sale of available-for-sale securities, net	554		(50)		830	(168)
Income from continuing operations, before income taxes	554		(50)		830	(168)
Income tax expense	(150)		13		(225)	45
Net income	404		(37)		605	(123)
Defined benefit pension plan items | Amount reclassified from AOCI
Comprehensive Income
Income from continuing operations, before income taxes	(105)		(68)		(210)	(136)
Income tax expense	28		18		57	37
Net income	(77)		(50)		(153)	(99)
Salaries and benefits	(105)		(68)		(210)	(136)
Investment Hedge | Amount reclassified from AOCI
Comprehensive Income
Income from continuing operations, before income taxes	(960)		(332)		833	126
Income tax expense	259		90		(225)	(34)
Net income	(701)		(242)		608	92
Interest on investment securities - taxable	$ (960)		$ (332)		$ 833	$ 126