Securities - Summary of Amortized Cost and Fair Value by Contractual Maturity of Securities Available for Sale Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]
Due in one year or less, Amortized Cost	$ 1,543	$ 1,080
Due after one year but less than five years, Amortized Cost	43,940	47,065
Due after five years but less than ten years, Amortized Cost	27,454	26,615
Due after ten years, Amortized Cost	7,994	9,044
Amortized Cost	80,931	83,804
Due in one year or less, Fair Value	1,545	1,079
Due after one year but less than five years, Fair Value	44,036	46,358
Due after five years but less than ten years, Fair Value	27,704	26,149
Due after ten years, Fair Value	7,884	8,646
Total available-for-sale securities, Fair Value	$ 81,169	$ 82,232	[1]

[1] Derived from audited December 31, 2018 Consolidated Financial Statements.