REGULATORY CAPITAL (Summary of actual capital amounts and ratios) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual Amount	$ 287,039	$ 131,895
Total capital (to risk-weighted assets), Actual Ratio	19.90%	12.50%
Total capital (to risk-weighted assets), For Capital Adequacy Amount	$ 115,636	$ 84,733
Total capital (to risk-weighted assets), For Capital Adequacy Ratio	8.00%	8.00%
Tier 1 common equity (to risk-weighted assets), Actual Amount	$ 221,803	$ 114,421
Tier 1 common equity (to risk-weighted assets), Actual Ratio	15.30%	10.80%
Tier 1 common equity (to risk-weighted assets), For Capital Adequacy Amount	$ 65,045	$ 47,662
Tier 1 common equity (to risk-weighted assets), For Capital Adequacy Ratio	4.50%	4.50%
Tier 1 capital (to risk-weighted assets), Actual Amount	$ 247,305	$ 119,923
Tier 1 capital (to risk-weighted assets), Actual Ratio	17.10%	11.30%
Tier 1 capital (to risk-weighted assets), For Capital Adequacy Amount	$ 86,726	$ 63,549
Tier 1 capital (to risk-weighted assets), For Capital Adequacy Ratio	6.00%	6.00%
Tier 1 capital (to average assets), Actual Amount	$ 247,305	$ 119,923
Tier 1 capital (to average assets), Actual Ratio	13.70%	10.50%
Tier 1 capital (to average assets), For Capital Adequacy Amount	$ 72,206	$ 45,742
Tier 1 capital (to average assets), For Capital Adequacy Ratio	4.00%	4.00%
Metropolitan Commercial Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual Amount	$ 280,317	$ 130,949
Total capital (to risk-weighted assets), Actual Ratio	19.40%	12.40%
Total capital (to risk-weighted assets), For Capital Adequacy Amount	$ 115,523	$ 84,619
Total capital (to risk-weighted assets), For Capital Adequacy Ratio	8.00%	8.00%
Total capital (to risk-weighted assets), To be Well Capitalized under Prompt Corrective Action Regulations Amount	$ 144,403	$ 105,774
Total capital (to risk-weighted assets), To be Well Capitalized under Prompt Corrective Action Regulations Ratio	10.00%	10.00%
Tier 1 common equity (to risk-weighted assets), Actual Amount	$ 265,076	$ 118,977
Tier 1 common equity (to risk-weighted assets), Actual Ratio	18.40%	11.30%
Tier 1 common equity (to risk-weighted assets), For Capital Adequacy Amount	$ 64,981	$ 47,598
Tier 1 common equity (to risk-weighted assets), For Capital Adequacy Ratio	4.50%	4.50%
Tier 1 common equity (to risk-weighted assets), To be Well Capitalized under Prompt Corrective Action Regulations Amount	$ 93,862	$ 68,753
Tier 1 common equity (to risk-weighted assets), To be Well Capitalized under Prompt Corrective Action Regulations Ratio	6.50%	6.50%
Tier 1 capital (to risk-weighted assets), Actual Amount	$ 265,076	$ 118,977
Tier 1 capital (to risk-weighted assets), Actual Ratio	18.40%	11.30%
Tier 1 capital (to risk-weighted assets), For Capital Adequacy Amount	$ 86,642	$ 63,465
Tier 1 capital (to risk-weighted assets), For Capital Adequacy Ratio	6.00%	6.00%
Tier 1 capital (to risk-weighted assets), To be Well Capitalized under Prompt Corrective Action Regulations Amount	$ 115,523	$ 84,619
Tier 1 capital (to risk-weighted assets), To be Well Capitalized under Prompt Corrective Action Regulations Ratio	8.00%	8.00%
Tier 1 capital (to average assets), Actual Amount	$ 265,076	$ 118,977
Tier 1 capital (to average assets), Actual Ratio	14.70%	10.40%
Tier 1 capital (to average assets), For Capital Adequacy Amount	$ 72,099	$ 45,703
Tier 1 capital (to average assets), For Capital Adequacy Ratio	4.00%	4.00%
Tier 1 capital (to average assets), To be Well Capitalized under Prompt Corrective Action Regulations Amount	$ 90,124	$ 57,128
Tier 1 capital (to average assets), To be Well Capitalized under Prompt Corrective Action Regulations Ratio	5.00%	5.00%
Total capital (to risk-weighted assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Amount	$ 133,573	$ 91,230
Total capital (to risk-weighted assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Ratio	9.30%	8.60%
Tier 1 common equity (to risk-weighted assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Amount	$ 83,032	$ 54,209
Tier 1 common equity (to risk-weighted assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Ratio	5.80%	5.10%
Tier 1 capital (to risk-weighted assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Amount	$ 104,692	$ 70,075
Tier 1 capital (to risk-weighted assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Ratio	7.30%	6.60%
Tier 1 capital (to average assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Amount	$ 72,099	$ 45,703
Tier 1 capital (to average assets), Minimum for Capital Adequacy plus Capital Conservation Buffer Ratio	4.00%	4.00%

The amount of total capital minimum for capital adequacy plus capital conservation buffer.

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Percentage of common equity tier one capital minimum for capital adequacy plus capital conservation buffer to total risk-weighted assets, as defined by regulatory framework.

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Percentage of common equity tier one capital required to be well capitalized to risk weighted assets ratio.

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The amount of common equity tier one minimum for capital adequacy plus capital conservation buffe risk-based capital, as defined by regulatory framework.

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Tier 1 leverage minimum for capital adequacy plus capital conservation buffer as defined in the regulations.

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Percentage of tier one leverage minimum for capital adequacy plus capital conservation buffer to average assets, as defined by regulatory framework.

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Tier 1 risk based minimum for capital adequacy plus capital conservation buffer as defined in the regulations.

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Percentage of tier one risk based minimum for capital adequacy plus capital conservation buffer to total risk-weighted assets, as defined by regulatory framework.

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The amount of total capital as defined in the regulations.

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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 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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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.

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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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