Loans and Leases Receivable

No definition available.

Name:	frme_LoansAndLeasesReceivable
Namespace Prefix:	frme_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for 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 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

+ Details

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_CreditLossStatusAxis=us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialRealEstateMember
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Loans and Allowance - Allowance for Credit Losses and Loan Portfolio by Loan Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance balances - Individually evaluated for impairment	$ 12,901	$ 689
Allowance balances - Collectively evaluated for impairment	117,747	79,595
Total allowance for loan losses	130,648	80,284	$ 80,552	$ 75,032
Loan balances - Individually evaluated for impairment	56,156	11,709
Loan balances - Collectively evaluated for impairment	9,180,857	8,434,292
Loans	9,243,174	8,459,310
Loans acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	6,161	13,309
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance balances - Individually evaluated for impairment	223	0
Allowance balances - Collectively evaluated for impairment	46,892	32,902
Total allowance for loan losses	47,115	32,902	32,657	30,420
Loan balances - Individually evaluated for impairment	1,258	457
Loan balances - Collectively evaluated for impairment	3,505,863	2,748,681
Loans	3,507,698	2,750,854
Commercial \| Loans acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	577	1,716
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance balances - Individually evaluated for impairment	12,246	231
Allowance balances - Collectively evaluated for impairment	38,824	28,547
Total allowance for loan losses	51,070	28,778	29,609	27,343
Loan balances - Individually evaluated for impairment	51,605	8,728
Loan balances - Collectively evaluated for impairment	3,805,808	3,821,660
Loans	3,862,997	3,840,266
Commercial Real Estate \| Loans acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	5,584	9,878
Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance balances - Individually evaluated for impairment	0	0
Allowance balances - Collectively evaluated for impairment	9,648	4,035
Total allowance for loan losses	9,648	4,035	3,964	3,732
Loan balances - Individually evaluated for impairment	2	4
Loan balances - Collectively evaluated for impairment	129,477	135,985
Loans	129,479	135,989
Construction \| Loans acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	0	0
Residential
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance balances - Individually evaluated for impairment	432	458
Allowance balances - Collectively evaluated for impairment	22,383	14,111
Total allowance for loan losses	22,815	14,569	$ 14,322	$ 13,537
Loan balances - Individually evaluated for impairment	3,291	2,520
Loan balances - Collectively evaluated for impairment	1,739,709	1,727,966
Loans	1,743,000	1,732,201
Residential \| Loans acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	$ 0	$ 1,715