Disclosures about Fair Value of Financial Instruments - Estimated Fair Values of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, Carrying Amount	$ 333,823	$ 371,023	$ 290,467	$ 233,068
Cash and cash equivalents, Estimated Fair Value	333,823	371,023
Investment securities, available for sale, Carrying Amount	396,194us-gaap_AvailableForSaleSecurities	416,685us-gaap_AvailableForSaleSecurities
Investment securities, available for sale, Estimated Fair Value	396,194us-gaap_AvailableForSaleSecurities	416,685us-gaap_AvailableForSaleSecurities
Loans held for sale, Carrying Amount	1,758,084us-gaap_LoansReceivableHeldForSaleNet	1,435,459us-gaap_LoansReceivableHeldForSaleNet
Loans held for sale, Estimated Fair Value	1,758,695	1,436,460
Loans receivable, net of allowance for loan losses, Carrying Amount	4,304,285	4,281,241
Loans receivable, net of allowance for loan losses, Estimated Fair Value	4,311,848	4,285,537
FHLB, Federal Reserve Bank and other restricted stock, Carrying Amount	81,798	82,002
FHLB and Federal Reserve Bank and other restricted stock, Estimated Fair Value	81,798	82,002
FDIC loss sharing receivable, Carrying Amount	3,427us-gaap_FDICIndemnificationAsset	2,320us-gaap_FDICIndemnificationAsset	8,272us-gaap_FDICIndemnificationAsset	10,046us-gaap_FDICIndemnificationAsset
FDIC loss sharing receivable, Estimated Fair Value	3,427	2,320
Derivatives assets	8,810us-gaap_DerivativeAssets	7,552us-gaap_DerivativeAssets
Deposits, Carrying Amount	4,893,321us-gaap_Deposits	4,532,538us-gaap_Deposits
Deposits, Estimated Fair Value	4,905,100us-gaap_DepositsFairValueDisclosure	4,540,507us-gaap_DepositsFairValueDisclosure
FHLB advances, Carrying Amount	1,545,000us-gaap_FederalHomeLoanBankAdvances	1,618,000us-gaap_FederalHomeLoanBankAdvances
FHLB advances, Estimated Fair Value	1,547,465us-gaap_AdvancesFairValueDisclosure	1,619,858us-gaap_AdvancesFairValueDisclosure
Other borrowings, Carrying Amount	88,250us-gaap_OtherBorrowings	88,250us-gaap_OtherBorrowings
Other borrowings, Estimated Fair Value	92,928cubi_BorrowingsFairValueDisclosure	92,069cubi_BorrowingsFairValueDisclosure
Subordinated debt, Carrying Amount	110,000us-gaap_SubordinatedDebt	110,000us-gaap_SubordinatedDebt
Subordinated debt, Estimated Fair Value	113,025	111,925
Derivatives liabilities	12,938us-gaap_DerivativeLiabilities	9,716us-gaap_DerivativeLiabilities
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, Estimated Fair Value	333,823	371,023
Investment securities, available for sale, Carrying Amount	22,305	24,270
Investment securities, available for sale, Estimated Fair Value	22,305	24,270
Loans held for sale, Estimated Fair Value	0	0
Loans receivable, net of allowance for loan losses, Estimated Fair Value	0	0
FHLB and Federal Reserve Bank and other restricted stock, Estimated Fair Value	0	0
FDIC loss sharing receivable, Estimated Fair Value	0	0
Derivatives assets	0	0
Deposits, Estimated Fair Value	3,059,457	2,820,875
FHLB advances, Estimated Fair Value	1,175,147	1,298,000
Other borrowings, Estimated Fair Value	67,678	66,944
Subordinated debt, Estimated Fair Value	0	0
Derivatives liabilities	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, Estimated Fair Value	0	0
Investment securities, available for sale, Carrying Amount	373,889	392,415
Investment securities, available for sale, Estimated Fair Value	373,889	392,415
Loans held for sale, Estimated Fair Value	1,676,891	1,335,668
Loans receivable, net of allowance for loan losses, Estimated Fair Value	0	0
FHLB and Federal Reserve Bank and other restricted stock, Estimated Fair Value	81,798	82,002
FDIC loss sharing receivable, Estimated Fair Value	0	0
Derivatives assets	8,723	7,509
Deposits, Estimated Fair Value	1,845,643	1,719,632
FHLB advances, Estimated Fair Value	372,318	321,858
Other borrowings, Estimated Fair Value	25,250	25,125
Subordinated debt, Estimated Fair Value	113,025	111,925
Derivatives liabilities	12,938	9,716
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, Estimated Fair Value	0	0
Investment securities, available for sale, Carrying Amount	0	0
Investment securities, available for sale, Estimated Fair Value	0	0
Loans held for sale, Estimated Fair Value	81,804	100,792
Loans receivable, net of allowance for loan losses, Estimated Fair Value	4,311,848	4,285,537
FHLB and Federal Reserve Bank and other restricted stock, Estimated Fair Value	0	0
FDIC loss sharing receivable, Estimated Fair Value	3,427	2,320
Derivatives assets	87	43
Deposits, Estimated Fair Value	0	0
FHLB advances, Estimated Fair Value	0	0
Other borrowings, Estimated Fair Value	0	0
Subordinated debt, Estimated Fair Value	0	0
Derivatives liabilities	$ 0	$ 0

Borrowings Fair Value Disclosure

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Fdic Indemnification Asset Fair Value Disclosure

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Federal Home Loan Bank Stock And Federal Reserve Bank Stock Fair Value

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Subordinated Debt Fair Value Disclosure

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Fair value of Federal Home Loan Bank (FHLBank) advances carried under the fair value option.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Carrying amount of receivable assets originating from the indemnification agreement with the Federal Deposit Insurance Corporation (FDIC), in which the FDIC is to partially cover losses.

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Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions.

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums over and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans and leases covered under loss sharing agreements.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount classified as loans attributable to disposal group held for sale or disposed of. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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