Fair Value Measurements - Available for Sale Securities Measured at Fair Value on a Recurring Basis (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets from Level 1 to Level 2		$ 0
Fair value of assets from Level 2 to Level 1		0
Financial assets transferred into Level 3		0
Financial assets transferred out of Level 3		0
Fair value of liabilities from Level 1 to Level 2		0
Fair value of liabilities from Level 2 to Level 1		0
Financial liabilities transferred into Level 3		0
Financial liabilities transferred out of Level 3		0
Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets transferred into Level 3	$ 1,000,000
Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets transferred into Level 3	138,000
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	196,313,000	148,903,000
Fair Value, Measurements, Recurring | Securities available-for-sale | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	9,066,000	15,887,000
Fair Value, Measurements, Recurring | Securities available-for-sale | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	10,570,000	6,865,000
Fair Value, Measurements, Recurring | Securities available-for-sale | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	21,120,000	14,194,000
Fair Value, Measurements, Recurring | Securities available-for-sale | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	62,850,000	44,836,000
Fair Value, Measurements, Recurring | Securities available-for-sale | U.S. Small Business Administration securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	22,451,000	15,423,000
Fair Value, Measurements, Recurring | Securities available-for-sale | Mortgage loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	69,699,000	51,195,000
Fair Value, Measurements, Recurring | Derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	(203,000)	(574,000)
Fair Value, Measurements, Recurring | Derivative | Interest rate lock commitments with customers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	557,000	503,000
Fair Value, Measurements, Recurring | Derivative | Individual forward sale commitments with investors
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	(203,000)	(574,000)
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	194,594,000	148,400,000
Fair Value, Measurements, Recurring | Level 2 | Securities available-for-sale | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	9,066,000	15,887,000
Fair Value, Measurements, Recurring | Level 2 | Securities available-for-sale | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	9,546,000	6,865,000
Fair Value, Measurements, Recurring | Level 2 | Securities available-for-sale | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	20,982,000	14,194,000
Fair Value, Measurements, Recurring | Level 2 | Securities available-for-sale | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	62,850,000	44,836,000
Fair Value, Measurements, Recurring | Level 2 | Securities available-for-sale | U.S. Small Business Administration securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	22,451,000	15,423,000
Fair Value, Measurements, Recurring | Level 2 | Securities available-for-sale | Mortgage loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	69,699,000	51,195,000
Fair Value, Measurements, Recurring | Level 2 | Derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	(8,000)	(540,000)
Fair Value, Measurements, Recurring | Level 2 | Derivative | Individual forward sale commitments with investors
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	(8,000)	(540,000)
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	1,719,000	503,000
Fair Value, Measurements, Recurring | Level 3 | Securities available-for-sale | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	1,024,000
Fair Value, Measurements, Recurring | Level 3 | Securities available-for-sale | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	138,000
Fair Value, Measurements, Recurring | Level 3 | Derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	(195,000)	(34,000)
Fair Value, Measurements, Recurring | Level 3 | Derivative | Interest rate lock commitments with customers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	557,000	503,000
Fair Value, Measurements, Recurring | Level 3 | Derivative | Individual forward sale commitments with investors
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	$ (195,000)	$ (34,000)