Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Assets:
Investments in equity securities	$ 3,279	$ 2,623
Total assets	187	317
Liabilities:
Transfer into Level 3	10,000	0
Fair Value Measured on Recurring Basis [Member]
Assets:
Total available-for-sale securities	218,640	246,924
Investments in equity securities	3,279	2,623
Total assets	262,039	250,263
Liabilities:
Total liabilities	1,883	604
Fair Value Measured on Recurring Basis [Member] | Contingent Consideration Liability [Member]
Liabilities:
Derivative liabilities	55	160
Fair Value Measured on Recurring Basis [Member] | Interest Rate Swap [Member]
Liabilities:
Derivative liabilities	541	249
Fair Value Measured on Recurring Basis [Member] | Credit Risk Contract [Member]
Liabilities:
Derivative liabilities	535	176
Fair Value Measured on Recurring Basis [Member] | Forward Loan Sale Commitments [Member]
Liabilities:
Derivative liabilities	752	19
Fair Value Measured on Recurring Basis [Member] | U.S. Government Corporations and Agencies [Member]
Assets:
Total available-for-sale securities		300
Fair Value Measured on Recurring Basis [Member] | State and Political Subdivisions [Member]
Assets:
Total available-for-sale securities	13,537	34,595
Fair Value Measured on Recurring Basis [Member] | Residential Mortgage-Backed Securities [Member]
Assets:
Total available-for-sale securities	114,163	118,460
Fair Value Measured on Recurring Basis [Member] | Collateralized Mortgage Obligations [Member]
Assets:
Total available-for-sale securities	5,321	2,361
Fair Value Measured on Recurring Basis [Member] | Corporate Bonds [Member]
Assets:
Total available-for-sale securities	85,619	91,208
Fair Value Measured on Recurring Basis [Member] | Equity Securities [Member]
Assets:
Total available-for-sale securities	818	1,004
Fair Value Measured on Recurring Basis [Member] | Money Market Mutual Funds [Member]
Assets:
Total available-for-sale securities	2,461	1,619
Fair Value Measured on Recurring Basis [Member] | Loans [Member]
Assets:
Net loans and leases held for investment	187	317
Loans held for sale	37,039
Fair Value Measured on Recurring Basis [Member] | Interest Rate Locks with Customers [Member]
Assets:
Derivative assets	2,894	399
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member]
Assets:
Total available-for-sale securities	0	0
Investments in equity securities	3,279	2,623
Total assets	3,279	2,623
Liabilities:
Total liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Contingent Consideration Liability [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Interest Rate Swap [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Credit Risk Contract [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Forward Loan Sale Commitments [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | U.S. Government Corporations and Agencies [Member]
Assets:
Total available-for-sale securities		0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | State and Political Subdivisions [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Residential Mortgage-Backed Securities [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Collateralized Mortgage Obligations [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Corporate Bonds [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Equity Securities [Member]
Assets:
Total available-for-sale securities	818	1,004
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Money Market Mutual Funds [Member]
Assets:
Total available-for-sale securities	2,461	1,619
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Loans [Member]
Assets:
Net loans and leases held for investment	0	0
Loans held for sale	0
Fair Value Measured on Recurring Basis [Member] | Level 1 [Member] | Interest Rate Locks with Customers [Member]
Assets:
Derivative assets	0	0
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member]
Assets:
Total available-for-sale securities	209,040	246,924
Investments in equity securities	0	0
Total assets	248,973	247,323
Liabilities:
Total liabilities	1,293	268
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Contingent Consideration Liability [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Interest Rate Swap [Member]
Liabilities:
Derivative liabilities	541	249
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Credit Risk Contract [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Forward Loan Sale Commitments [Member]
Liabilities:
Derivative liabilities	752	19
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | U.S. Government Corporations and Agencies [Member]
Assets:
Total available-for-sale securities		300
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | State and Political Subdivisions [Member]
Assets:
Total available-for-sale securities	13,537	34,595
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Residential Mortgage-Backed Securities [Member]
Assets:
Total available-for-sale securities	114,163	118,460
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Collateralized Mortgage Obligations [Member]
Assets:
Total available-for-sale securities	5,321	2,361
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Corporate Bonds [Member]
Assets:
Total available-for-sale securities	76,019	91,208
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Equity Securities [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Money Market Mutual Funds [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Loans [Member]
Assets:
Net loans and leases held for investment	0	0
Loans held for sale	37,039
Fair Value Measured on Recurring Basis [Member] | Level 2 [Member] | Interest Rate Locks with Customers [Member]
Assets:
Derivative assets	2,894	399
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member]
Assets:
Total available-for-sale securities	9,600	0
Investments in equity securities	0	0
Total assets	9,787	317
Liabilities:
Total liabilities	590	336
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Contingent Consideration Liability [Member]
Liabilities:
Derivative liabilities	55	160
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Interest Rate Swap [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Credit Risk Contract [Member]
Liabilities:
Derivative liabilities	535	176
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Forward Loan Sale Commitments [Member]
Liabilities:
Derivative liabilities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | U.S. Government Corporations and Agencies [Member]
Assets:
Total available-for-sale securities		0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | State and Political Subdivisions [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Residential Mortgage-Backed Securities [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Collateralized Mortgage Obligations [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Corporate Bonds [Member]
Assets:
Total available-for-sale securities	9,600	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Equity Securities [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Money Market Mutual Funds [Member]
Assets:
Total available-for-sale securities	0	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Loans [Member]
Assets:
Net loans and leases held for investment	187	317
Loans held for sale	0
Fair Value Measured on Recurring Basis [Member] | Level 3 [Member] | Interest Rate Locks with Customers [Member]
Assets:
Derivative assets	$ 0	$ 0