Loans and Allowance for Credit Losses Total Impaired Loans by Class Segments (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Impaired Financing Receivables [Line Items]
With a Related Allowance	$ 77,579	$ 81,504
Without a Related Allowance	64,456	72,368
Unpaid Principal Balance	142,035	153,872
Real estate - commercial mortgage
Impaired Financing Receivables [Line Items]
With a Related Allowance	19,888	27,437
Without a Related Allowance	39,393	44,613
Unpaid Principal Balance	59,281	72,050
Commercial
Impaired Financing Receivables [Line Items]
With a Related Allowance	22,635	19,822
Without a Related Allowance	22,735	24,281
Unpaid Principal Balance	45,370	44,103
Real estate - residential mortgage
Impaired Financing Receivables [Line Items]
With a Related Allowance	26,315	25,423
Without a Related Allowance	2,328	2,328
Unpaid Principal Balance	28,643	27,751
Real estate - home equity
Impaired Financing Receivables [Line Items]
With a Related Allowance	7,307	7,126
Without a Related Allowance	0	0
Unpaid Principal Balance	7,307	7,126
Construction
Impaired Financing Receivables [Line Items]
With a Related Allowance	1,406	1,661
Without a Related Allowance	0	0
Unpaid Principal Balance	1,406	1,661
Consumer
Impaired Financing Receivables [Line Items]
With a Related Allowance	3	3
Without a Related Allowance	0	0
Unpaid Principal Balance	3	3
Leases and other loans
Impaired Financing Receivables [Line Items]
With a Related Allowance	25	32
Without a Related Allowance	0	1,146
Unpaid Principal Balance	$ 25	$ 1,178

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.

No definition available.

+ Details

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

- Definition

Amount of financing receivable individually evaluated for credit loss. Excludes financing receivable collectively evaluated for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.5.a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480418/310-10-S99-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-11C

+ Details

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

- Definition

Amount of financing receivable with allowance for credit loss evaluated on individual basis. Excludes financing receivable evaluated on collective basis.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 35
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479366/326-20-35-6

+ Details

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

- Definition

Amount of financing receivable without allowance for credit loss evaluated on individual basis. Excludes financing receivable evaluated on collective basis.

+ References

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fult_CommercialSecuredMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fult_ConstructionCommercialResidentialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fult_ConsumerDirectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fult_LeasingAndOtherAndOverdraftsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: