Regulatory Matters - Schedule of Actual Capital Amounts and Ratios (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 leverage	$ 1,717,530	$ 1,209,407
Common equity tier 1 capital	1,717,530	1,172,454
Tier 1 risk-based capital	1,717,530	1,209,407
Total risk-based capital	1,959,393	1,403,311
Tier 1 leverage	683,890	479,940
Common equity tier 1 capital	740,657	536,930
Tier 1 risk-based capital	987,543	715,907
Total risk-based capital	1,316,724	954,542
Tier 1 risk-based capital	987,543	715,907
Total risk-based capital	$ 1,645,905	$ 1,193,178
Tier 1 leverage	10.00%	10.10%
Common equity tier 1 capital	10.40%	9.80%
Tier 1 risk-based capital	10.40%	10.10%
Total risk-based capital	11.90%	11.80%
Tier 1 leverage	4.00%	4.00%
Common equity tier 1 capital	4.50%	4.50%
Tier 1 risk-based capital	6.00%	6.00%
Total risk-based capital	8.00%	8.00%
Tier 1 risk-based capital	6.00%	6.00%
Total risk-based capital	10.00%	10.00%
Cadence Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Tier 1 leverage	$ 1,889,679	$ 1,327,974
Common equity tier 1 capital	1,839,679	1,277,974
Tier 1 risk-based capital	1,889,679	1,327,974
Total risk-based capital	2,020,268	1,447,719
Tier 1 leverage	683,640	479,667
Common equity tier 1 capital	740,358	536,285
Tier 1 risk-based capital	987,144	715,047
Total risk-based capital	1,316,192	953,396
Tier 1 leverage	854,551	599,584
Common equity tier 1 capital	1,069,406	774,634
Tier 1 risk-based capital	1,316,192	953,396
Total risk-based capital	$ 1,645,240	$ 1,191,745
Tier 1 leverage	11.10%	11.10%
Common equity tier 1 capital	11.20%	10.70%
Tier 1 risk-based capital	11.50%	11.10%
Total risk-based capital	12.30%	12.10%
Tier 1 leverage	4.00%	4.00%
Common equity tier 1 capital	4.50%	4.50%
Tier 1 risk-based capital	6.00%	6.00%
Total risk-based capital	8.00%	8.00%
Tier 1 leverage	5.00%	5.00%
Common equity tier 1 capital	6.50%	6.50%
Tier 1 risk-based capital	8.00%	8.00%
Total risk-based capital	10.00%	10.00%

Common equity tier one capital to risk weighted assets.

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Tier one risk based common equity required to be well capitalized to risk weighted assets.

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The amount of total capital as defined in the regulations.

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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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Amount of Common Equity Tier One Risk-based Capital, as defined by regulatory framework.

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Amount of Common Equity Tier 1 Risk-based Capital required to be categorized as adequately capitalized under regulatory framework for prompt corrective action.

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

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