Loans and Leases Receivable and Allowance for Credit Losses on Loans and Leases - Summary of Loans Modified in Troubled Debt Restructurings and Related Recorded Investment (Detail) $ in Thousands	9 Months Ended
Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans \| loan	36	21
Recorded Investment \| $	$ 585	$ 302
Manufactured housing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans \| loan	1	2
Recorded Investment \| $	$ 46	$ 71
Residential real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans \| loan	1	0
Recorded Investment \| $	$ 119	$ 0
Installment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans \| loan	34	19
Recorded Investment \| $	$ 420	$ 231

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

- Definition

Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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