Regulatory Capital Requirements - Components of Regulatory Capital (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total shareholders' equity	$ 301,484	$ 294,265	$ 285,480	$ 249,806
Accumulated other comprehensive loss	(24,077)	(18,685)
United Community [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total shareholders' equity	301,484	294,265
Accumulated other comprehensive loss	24,077	18,701
Intangible assets	(23,970)	(23,416)
Disallowed deferred tax assets		(3,806)
Tier 1 Capital	301,591	285,744
Allowance for loan losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets	21,405	21,202
Total risk-based capital	322,996	306,946
Home Savings [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total shareholders' equity	272,816	276,494
Accumulated other comprehensive loss	24,092	18,701
Intangible assets	(21,160)	(20,903)
Disallowed deferred tax assets		(2,515)
Tier 1 Capital	275,748	271,777
Allowance for loan losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets	21,338	21,151
Total risk-based capital	$ 297,086	$ 292,928