Allowance for Loan and Lease Losses - Activity in Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually	$ 15,001	$ 14,153	$ 13,366
Collectively	2,197,096	1,748,412	1,764,533
Total Financing Receivables	2,212,097	1,762,565	1,777,899
Commercial, Residential, and Farm Land Real Estate Portfolio Segment [Member] \| Real Estate Sector [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually	13,272	12,746	11,751
Collectively	1,584,417	1,389,368	1,426,425
Total Financing Receivables	1,597,689	1,402,114	1,438,176
Agricultural Portfolio Segment [Member] \| Agricultural Sector [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually	2	5	6
Collectively	48,514	48,031	51,503
Total Financing Receivables	48,516	48,036	51,509
Commercial Portfolio Segment [Member] \| Commercial and Industrial Sector [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually	1,383	977	837
Collectively	558,243	303,658	279,091
Total Financing Receivables	559,626	304,635	279,928
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually	344	425	772
Collectively	5,922	7,355	7,514
Total Financing Receivables	$ 6,266	$ 7,780	$ 8,286

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

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- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121593590&loc=d3e4428-111522

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