Regulatory Capital Requirements - Actual and Statutory Required Capital Amounts and Ratios (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
United Community [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual Amount	$ 328,992	$ 306,946
Tier 1 capital (to risk-weighted assets), Actual Amount	307,660	285,744
Common equity Tier 1 capital (to risk-weighted assets), Actual Amount	307,660	285,744
Tier 1 capital (to average assets), Actual Amount	$ 307,660	$ 285,744
Total capital (to risk-weighted assets), Actual Ratio	15.37%	15.35%
Tier 1 capital (to risk-weighted assets), Actual Ratio	14.38%	14.29%
Common equity Tier 1 capital (to risk-weighted assets), Actual Ratio	14.38%	14.29%
Tier 1 capital (to average assets), Actual Ratio	11.11%	10.93%
Total capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Amount	$ 211,339	$ 184,881
Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Amount	168,536	144,907
Common equity Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Amount	136,434	114,926
Tier 1 capital (to average assets), Minimum Capital Requirements Per Regulation Amount	$ 110,735	$ 104,588
Total capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Ratio	9.88%	9.25%
Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Ratio	7.88%	7.25%
Common equity Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Ratio	6.38%	5.75%
Tier 1 capital (to average assets), Minimum Capital Requirements Per Regulation Ratio	4.00%	4.00%
Total capital (to risk-weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%
Tier 1 capital (to risk-weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.00%
Home Savings [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual Amount	$ 297,367	$ 292,928
Tier 1 capital (to risk-weighted assets), Actual Amount	276,103	271,777
Common equity Tier 1 capital (to risk-weighted assets), Actual Amount	276,103	271,777
Tier 1 capital (to average assets), Actual Amount	$ 276,103	$ 271,777
Total capital (to risk-weighted assets), Actual Ratio	13.95%	14.70%
Tier 1 capital (to risk-weighted assets), Actual Ratio	12.96%	13.64%
Common equity Tier 1 capital (to risk-weighted assets), Actual Ratio	12.96%	13.64%
Tier 1 capital (to average assets), Actual Ratio	10.02%	10.42%
Total capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Amount	$ 210,458	$ 184,235
Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Amount	167,834	144,400
Common equity Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Amount	135,866	114,525
Tier 1 capital (to average assets), Minimum Capital Requirements Per Regulation Amount	$ 110,200	$ 104,308
Total capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Ratio	9.88%	9.25%
Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Ratio	7.88%	7.25%
Common equity Tier 1 capital (to risk-weighted assets), Minimum Capital Requirements Per Regulation Ratio	6.38%	5.75%
Tier 1 capital (to average assets), Minimum Capital Requirements Per Regulation Ratio	4.00%	4.00%
Total capital (to risk-weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 213,123	$ 199,173
Tier 1 capital (to risk-weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	170,498	159,338
Common equity Tier 1 capital (to risk-weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	138,530	129,463
Tier 1 capital (to average assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 137,750	$ 130,385
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%	8.00%
Common equity Tier 1 capital (to risk-weighted assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50%	6.50%
Tier 1 capital (to average assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00%	5.00%

Common equity tier one capital required for capital adequacy to risk weighted assets.

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Common equity tier one capital required to be well capitalized to risk weighted assets.

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Common equity tier one capital to risk weighted assets.

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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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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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Amount of Common Equity Tier 1 Risk-based Capital required to be categorized as well-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 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 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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Tier 1 capital divided by risk weighted assets as defined by regulations.

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