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Allowance for Credit Losses and Credit Quality of Loans (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Allowance for Credit Losses [Abstract]
Allowance for credit losses	$ 105,000	$ 110,000	$ 100,000	$ 75,999
Percentage of allowance of credit losses	1.38%	1.47%
Retained earnings	$ 777,170	$ 749,056
Loans purchased with credit deterioration	0	0
Accrued Interest Receivable [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses	500	600
AIR on loans	$ 22,600	23,700
Write-off of uncollectible interest period	120 days
ASU 2016-13 [Member] | Loans [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses				3,000
Retained earnings				(2,300)
Deferred tax asset				700
Consumer Loans [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses	$ 34,580	37,803	$ 37,546	$ 32,122
Amount of loans purchased		$ 51,900
Discount on loans purchased		1.00%
Allowance for credit losses on loans purchased		$ 3,600

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- Definition

The discount percentage on loans purchased.

+ References

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Allowance for credit losses as a percentage of financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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The write-off period of uncollectible interest of delinquent loans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of loans purchased with credit deterioration during the period.

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Reserve for loans impairments recorded after acquisition as a result of current information and events which result in it being probable that estimated cash flows will be less than previously expected or because actual cash flows are less than cash flows previously expected. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting.

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Amount, after allowance for credit loss, of accrued interest on financing receivable.

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

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