Financing Receivable, Allowance For Credit Loss, Forecast Period

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- Definition

Financing Receivable, Allowance for Credit Loss, Qualitative Reserve, Period Increase (Decrease)

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- Definition

Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Percent

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- Definition

Financing Receivable, before Allowance for Credit Loss, Period Increase (Decrease)

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- Definition

Financing Receivable, Credit Loss, Expense (Reversal), COVID-19 Assessment, Forecast Component

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- Definition

Financing Receivable, Credit Loss, Expense (Reversal), Period Increase (Decrease)

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- Definition

Amount, after recovery, of writeoff of financing receivable, charged against allowance for credit loss.

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- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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- 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.

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- Definition

Amount, before allowance for credit loss, of financing receivable.

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Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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- Definition

Amount of credit loss expense (reversal of expense) for financing receivable.

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Allowance for Credit Losses - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss	$ 115,101	$ 96,850	$ 117,612		$ 62,224
Provision for credit losses on loans	3,301	18,430
Net loan charge-offs	$ 5,812	$ 11,156
Net loan charge-offs, percent	0.33%	0.63%
Portfolio loans, net of unearned income	$ 7,183,168		7,225,860
Total loans	7,068,067		7,108,248
COVID-19
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, credit loss, expense (reversal), period increase (decrease)	(16,900)	$ (20,000)
Provision for credit losses on loans	3,100
ACL provision, COVID-19 assessment, revised forecast		14,300
Financing receivable, allowance for credit loss, qualitative reserve, period increase (decrease)	$ 2,700	3,100
Forecast period	2 years
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Portfolio loans, net of unearned income	$ 5,676,683		5,673,707
Nonperforming
Financing Receivable, Allowance for Credit Loss [Line Items]
Portfolio loans, net of unearned income	132,413		146,774
Nonperforming \| COVID-19
Financing Receivable, Allowance for Credit Loss [Line Items]
Increase (decrease) in non-performing loans	61,400
Portfolio loans, net of unearned income	135,200	73,800
Commercial and industrial \| Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss	14,663	19,870	16,100		15,681
Provision for credit losses on loans	2,728	6,196
Net loan charge-offs	4,165	9,860
Portfolio loans, net of unearned income	1,699,588		1,559,552
Commercial and industrial \| Nonperforming \| Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Portfolio loans, net of unearned income	12,416		16,985
Commercial real estate \| Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss	66,842	42,611	65,656		30,577
Provision for credit losses on loans	1,996	7,639
Net loan charge-offs	810	$ 415
Portfolio loans, net of unearned income	2,780,327		2,791,947
Commercial real estate \| Commercial \| Hotel \| COVID-19
Financing Receivable, Allowance for Credit Loss [Line Items]
Portfolio loans, net of unearned income	53,600
Commercial real estate \| Nonperforming \| Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Portfolio loans, net of unearned income	95,074		$ 101,070
CARES Act, Paycheck Protection Program Loans \| Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans	$ 499,100
Impact of new accounting standard
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss				$ 27,400	27,352
Impact of new accounting standard \| S&T Legacy Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss				8,200
Impact of new accounting standard \| Commercial and industrial \| Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss				9,900	7,853
Impact of new accounting standard \| Commercial real estate \| Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss					$ 4,810
Impact of new accounting standard \| DNB
Financing Receivable, Allowance for Credit Loss [Line Items]
Adjustment to allowance for credit loss				$ 9,300