Fair Value Measurements - Financial Assets and Financial Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at estimated fair value	$ 123,610	$ 100,717
Equity investments	10,002	9,655
Interest rate swap liability	7,300	1,800
Other real estate owned	865	1,381
Items Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at estimated fair value	123,610	100,717
Equity investments	10,002	9,655
Interest rate swap asset	6,989	1,722
Interest rate swap liability	(7,274)	(1,813)
Items Measured on a Recurring Basis | Level 1 Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at estimated fair value	0	0
Equity investments	10,002	9,655
Interest rate swap asset	0	0
Interest rate swap liability	0	0
Items Measured on a Recurring Basis | Level 2 Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at estimated fair value	123,610	100,717
Equity investments	0	0
Interest rate swap asset	6,989	1,722
Interest rate swap liability	(7,274)	(1,813)
Items Measured on a Recurring Basis | Level 3 Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at estimated fair value	0	0
Equity investments	0	0
Interest rate swap asset	0	0
Interest rate swap liability	0	0
Items Measured on a Non-Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	865	1,381
Items Measured on a Non-Recurring Basis | Loans measured for impairment based on the fair value of the underlying collateral
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	9,067	11,639
Items Measured on a Non-Recurring Basis | Level 1 Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Items Measured on a Non-Recurring Basis | Level 1 Inputs | Loans measured for impairment based on the fair value of the underlying collateral
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Items Measured on a Non-Recurring Basis | Level 2 Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Items Measured on a Non-Recurring Basis | Level 2 Inputs | Loans measured for impairment based on the fair value of the underlying collateral
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	0
Items Measured on a Non-Recurring Basis | Level 3 Inputs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	865	1,381
Items Measured on a Non-Recurring Basis | Level 3 Inputs | Loans measured for impairment based on the fair value of the underlying collateral
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	$ 9,067	$ 11,639