Actual Capital Amounts and Ratios for Community Bank in Comparison to Minimum Amounts and Ratios Required (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Leverage Capital Amount
Total regulatory capital, Leverage Capital Amount	$ 3,731,430us-gaap_TierOneLeverageCapital	$ 3,664,082us-gaap_TierOneLeverageCapital
Minimum for capital adequacy purposes, Leverage capital amount	1,856,755	1,745,857
Excess, Leverage capital amount	1,874,675us-gaap_ExcessTierOneLeverageCapital	1,918,225us-gaap_ExcessTierOneLeverageCapital
Leverage Capital Ratio
Total regulatory capital, Leverage capital ratio	8.04%	8.39%
Minimum for capital adequacy purposes, Leverage capital ratio	4.00%	4.00%
Excess, Leverage capital ratio	4.04%	4.39%
Tier 1 Amount
Total regulatory capital, Risk-Based Capital, Tier 1 Amount	3,731,430us-gaap_TierOneRiskBasedCapital	3,664,082us-gaap_TierOneRiskBasedCapital
Minimum for capital adequacy purposes, Risk-Based Capital, Tier 1 Amount	1,213,802	1,141,644
Excess, Risk-Based Capital, Tier 1 Amount	2,517,628us-gaap_ExcessTierOneRiskBasedCapital	2,522,438us-gaap_ExcessTierOneRiskBasedCapital
Tier 1 Ratio
Total regulatory capital, Risk-Based Capital, Tier 1 Ratio	12.30%	12.84%
Minimum for capital adequacy purposes, Risk-Based Capital, Tier 1 Ratio	4.00%	4.00%
Excess, Risk-Based Capital, Tier 1 Ratio	8.30%	8.84%
Total Amount
Total regulatory capital, Risk-Based Capital, Total Amount	3,919,248us-gaap_Capital	3,870,921us-gaap_Capital
Minimum for capital adequacy purposes, Risk-Based Capital, Total Amount	2,427,605	2,283,287
Excess, Risk-Based Capital, Total Amount	1,491,643us-gaap_ExcessCapital	1,587,634us-gaap_ExcessCapital
Total Ratio
Total regulatory capital, Risk-Based Capital, Total Ratio	12.92%us-gaap_CapitalToRiskWeightedAssets	13.56%us-gaap_CapitalToRiskWeightedAssets
Minimum for capital adequacy purposes, Risk-Based Capital, Total Ratio	8.00%	8.00%
Excess, Risk-Based Capital, Total Ratio	4.92%	5.56%
New York Community Bank
Leverage Capital Amount
Total regulatory capital, Leverage Capital Amount	3,285,870	3,196,870
Minimum for capital adequacy purposes, Leverage capital amount	1,701,174	1,627,696
Excess, Leverage capital amount	1,584,696	1,569,174
Leverage Capital Ratio
Total regulatory capital, Leverage capital ratio	7.73%	7.86%
Minimum for capital adequacy purposes, Leverage capital ratio	4.00%	4.00%
Excess, Leverage capital ratio	3.73%	3.86%
Tier 1 Amount
Total regulatory capital, Risk-Based Capital, Tier 1 Amount	3,285,870	3,196,870
Minimum for capital adequacy purposes, Risk-Based Capital, Tier 1 Amount	1,093,835	1,046,793
Excess, Risk-Based Capital, Tier 1 Amount	2,192,035	2,150,077
Tier 1 Ratio
Total regulatory capital, Risk-Based Capital, Tier 1 Ratio	12.02%	12.22%
Minimum for capital adequacy purposes, Risk-Based Capital, Tier 1 Ratio	4.00%	4.00%
Excess, Risk-Based Capital, Tier 1 Ratio	8.02%	8.22%
Total Amount
Total regulatory capital, Risk-Based Capital, Total Amount	3,461,741	3,391,944
Minimum for capital adequacy purposes, Risk-Based Capital, Total Amount	2,187,669	2,093,586
Excess, Risk-Based Capital, Total Amount	$ 1,274,072	$ 1,298,358
Total Ratio
Total regulatory capital, Risk-Based Capital, Total Ratio	12.66%	12.96%
Minimum for capital adequacy purposes, Risk-Based Capital, Total Ratio	8.00%	8.00%
Excess, Risk-Based Capital, Total Ratio	4.66%	4.96%

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

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The amount by which the company's Total Capital exceeds the minimum required for capital adequacy purposes.

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The amount of excess Total Capital divided by risk weighted assets which are assets that are weighted for credit risk according to a formula used by the Reserve Bank.

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The amount by which the company's Tier 1 Leverage Capital exceeds the minimum required for capital adequacy purposes.

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The amount of excess Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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The amount by which the company's Tier 1 Risk Based Capital exceeds the minimum required for capital adequacy purposes.

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The amount of excess Tier 1 Risk Based Capital (which consists of the types of financial capital considered the most reliable and liquid, primarily Shareholders' equity. Examples of Tier 1 capital are common stock or unit, preferred stock or unit that is irredeemable and noncumulative, and retained earnings) divided by risk-weighted assets which are assets that are weighted for credit risk according to a formula used by the Reserve Bank.

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

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

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