Regulatory Matters - Summary of Capital Amounts, Tier 1 Risk Based and Tier 1 Leveraged Ratios (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity Tier 1 (to risk weighted assets), Actual Amount	$ 454,889cubi_TierOneCommonEquity
Total capital (to risk weighted assets), Actual Amount	587,473us-gaap_Capital	578,644us-gaap_Capital
Tier 1 capital (to risk weighted assets), Actual Amount	454,889us-gaap_TierOneRiskBasedCapital	437,712us-gaap_TierOneRiskBasedCapital
Tier 1 capital (to average assets), Actual Amount	454,889us-gaap_TierOneLeverageCapital	437,712us-gaap_TierOneLeverageCapital
Common equity Tier 1 ( to risk weighted assets), Actual Ratio	8.25%
Total capital (to risk weighted assets), Actual Ratio	10.66%us-gaap_CapitalToRiskWeightedAssets	11.09%us-gaap_CapitalToRiskWeightedAssets
Tier 1 capital (to risk weighted assets), Actual Ratio	8.25%	8.39%
Tier 1 capital (to average assets), Actual Ratio	6.72%	6.69%
Common equity Tier 1 (to risk weighted assets), For Capital Adequacy Purposes Amount	248,013
Total capital (to risk weighted assets), For Capital Adequacy Purposes Amount	440,913	417,473
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes Amount	330,684	208,737
Tier 1 capital (to average assets), For Capital Adequacy Purposes Amount	270,915	261,622
Common equity Tier 1 (to risk weighted assets), For Capital Adequacy Purposes Ratio	4.50%
Total capital (to risk weighted assets), For Capital Adequacy Purposes Ratio	8.00%	8.00%
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes Ratio	6.00%	4.00%
Tier 1 capital (to average assets), For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier 1 capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%
Customers Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity Tier 1 (to risk weighted assets), Actual Amount	496,018
Total capital (to risk weighted assets), Actual Amount	639,584	621,894
Tier 1 capital (to risk weighted assets), Actual Amount	496,018	480,963
Tier 1 capital (to average assets), Actual Amount	496,018	480,963
Common equity Tier 1 ( to risk weighted assets), Actual Ratio	9.05%
Total capital (to risk weighted assets), Actual Ratio	11.66%	11.98%
Tier 1 capital (to risk weighted assets), Actual Ratio	9.05%	9.27%
Tier 1 capital (to average assets), Actual Ratio	7.35%	7.39%
Common equity Tier 1 (to risk weighted assets), For Capital Adequacy Purposes Amount	246,741
Total capital (to risk weighted assets), For Capital Adequacy Purposes Amount	438,651	415,141
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes Amount	328,988	207,570
Tier 1 capital (to average assets), For Capital Adequacy Purposes Amount	269,801	260,462
Common equity Tier 1 (to risk weighted assets), For Capital Adequacy Purposes Ratio	4.50%
Total capital (to risk weighted assets), For Capital Adequacy Purposes Ratio	8.00%	8.00%
Tier 1 capital (to risk weighted assets), For Capital Adequacy Purposes Ratio	6.00%	4.00%
Tier 1 capital (to average assets), For Capital Adequacy Purposes Ratio	4.00%	4.00%
Common equity Tier 1 (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	356,404
Total capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	548,314	518,926
Tier 1 capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	438,651	311,356
Tier 1 capital (to average assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 337,251	$ 325,577
Common equity Tier 1 (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50%
Total capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%	10.00%
Tier 1 capital (to risk weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%	6.00%
Tier 1 capital (to average assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00%	5.00%

Tier One Common Capital Required for Capital Adequacy to Risk Weighted Assets

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Tier One Common Capital Required to be Well Capitalized to Risk Weighted Assets

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Tier One Common Capital to Risk Weighted Assets

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Tier One Common Equity

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Tier One Common Equity Required to be Well Capitalized

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The amount of total capital as defined in the regulations.

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The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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