Allowance for Loan and Lease Losses - Allowance for Credit Losses - Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 9,923	$ 9,750	$ 9,750
Charge-offs	(642)	(1,130)	(4,873)
Recoveries	372	518	2,496
Provision	1,800	300	2,550
Ending balance	11,453	9,438	9,923
Unallocated [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	132	30	30
Provision	(120)	52	102
Ending balance	12	82	132
Real Estate Sector [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	5,635	5,831	5,831
Charge-offs			(1,190)
Recoveries	72	175	647
Provision	1,608	88	347
Ending balance	7,315	6,094	5,635
Agricultural Sector [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	193	256	256
Provision	42	(37)	(63)
Ending balance	235	219	193
Commercial and Industrial and Mortgage Warehouse Sector [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,685	2,394	2,394
Charge-offs	(25)	(579)	(1,274)
Recoveries	28	41	690
Provision	66	58	875
Ending balance	2,754	1,914	2,685
Consumer Loans Sector [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,278	1,239	1,239
Charge-offs	(617)	(551)	(2,409)
Recoveries	272	302	1,159
Provision	204	139	1,289
Ending balance	$ 1,137	$ 1,129	$ 1,278