Investments in Affiliated Companies - Summary Statement of Income (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Income - interest income from subordinated debentures issued by HopFed Bancorp, Inc.	$ 9,474	$ 9,344	$ 9,115	$ 8,798	$ 8,541	$ 8,635	$ 8,419	$ 8,160	$ 36,731	$ 33,755	$ 31,727
Majority-Owned Subsidiary, Unconsolidated [Member]
Schedule of Equity Method Investments [Line Items]
Income - interest income from subordinated debentures issued by HopFed Bancorp, Inc.									555	449
Net income									$ 555	$ 449