Securities - Trading Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 9,809	$ 7,786
Corporate equity securities
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	7,946	5,828
Mutual Funds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	807	1,058
Certificates of deposit
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	350	268
Corporate notes and bonds
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	655	581
U.S. Gov’t sponsored entities
Debt and Equity Securities, FV-NI [Line Items]
Trading securities	$ 51	$ 51