Loans (Allowance for Loan Losses and Recorded Investment in Loans) (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Allowance for Loan Losses:
Individually Evaluated for Impairment					$ 2,971
Collectively Evaluated for Impairment					12,902
Total Ending Allowance Balance		$ 46,768	$ 42,431	$ 31,931	16,278	$ 15,869	$ 16,239	$ 15,823
Loans:
Loans Individually Evaluated for Impairment					6,269
Loans Collectively Evaluated for Impairment					3,076,835
Total	[1]				3,095,902
Accrued interest included in recorded investment		14,995			13,929
Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					405
Loans:
Total					12,798
Commercial and Industrial Loans and Leases
Allowance for Loan Losses:
Individually Evaluated for Impairment					2,412
Collectively Evaluated for Impairment					2,387
Total Ending Allowance Balance					4,799	4,603	2,992	2,953
Loans:
Loans Individually Evaluated for Impairment					4,707
Loans Collectively Evaluated for Impairment					585,328
Total	[1]				591,403
Commercial and Industrial Loans and Leases | Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					0
Loans:
Total					1,368
Commercial Real Estate Loans
Allowance for Loan Losses:
Individually Evaluated for Impairment					559
Collectively Evaluated for Impairment					3,733
Total Ending Allowance Balance		28,382	22,369		4,692	4,300	5,841	5,291
Loans:
Loans Individually Evaluated for Impairment					1,562
Loans Collectively Evaluated for Impairment					1,491,090
Total	[1]				1,499,864
Commercial Real Estate Loans | Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					400
Loans:
Total					7,212
Agricultural Loans
Allowance for Loan Losses:
Individually Evaluated for Impairment					0
Collectively Evaluated for Impairment					5,315
Total Ending Allowance Balance		6,715	7,030		5,315	5,352	5,725	5,776
Loans:
Loans Individually Evaluated for Impairment					0
Loans Collectively Evaluated for Impairment					387,710
Total	[1]				390,871
Agricultural Loans | Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					0
Loans:
Total					3,161
Home Equity Loans
Allowance for Loan Losses:
Individually Evaluated for Impairment					0
Collectively Evaluated for Impairment					200
Total Ending Allowance Balance		995	1,062		200	194	258	229
Loans:
Loans Individually Evaluated for Impairment					0
Loans Collectively Evaluated for Impairment					226,406
Total	[1]				226,775
Home Equity Loans | Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					0
Loans:
Total					369
Consumer Loans
Allowance for Loan Losses:
Individually Evaluated for Impairment					0
Collectively Evaluated for Impairment					434
Total Ending Allowance Balance		492	496		434	418	422	420
Loans:
Loans Individually Evaluated for Impairment					0
Loans Collectively Evaluated for Impairment					81,429
Total	[1]				81,429
Consumer Loans | Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					0
Loans:
Total					0
Residential Mortgage Loans
Allowance for Loan Losses:
Individually Evaluated for Impairment					0
Collectively Evaluated for Impairment					328
Total Ending Allowance Balance		2,141	2,360		333	362	349	472
Loans:
Loans Individually Evaluated for Impairment					0
Loans Collectively Evaluated for Impairment					304,872
Total	[1]				305,560
Residential Mortgage Loans | Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					5
Loans:
Total					688
Unallocated
Allowance for Loan Losses:
Individually Evaluated for Impairment					0
Collectively Evaluated for Impairment					505
Total Ending Allowance Balance		$ 0	$ 0		505	$ 640	$ 652	$ 682
Unallocated | Acquired with Deteriorated Credit Quality
Allowance for Loan Losses:
Total Ending Allowance Balance					$ 0

[1] Total recorded investment in loans includes $13,929 in accrued interest.