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Investment Securities - Available-for-Sale Securities Amortized Cost and Fair Value (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Total	$ 508,337,000	$ 373,038,000
Available-for-sale, gross unrealized gains	13,752,000	19,393,000
Gross Unrealized (Losses)	(3,521,000)	(80,000)
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	518,568,000	392,351,000
Accrued interest	1,900,000	1,900,000
MBS pass-through securities issued by FHLMC and FNMA
Debt Securities, Available-for-sale [Line Items]
Total	65,871,000	50,686,000
Available-for-sale, gross unrealized gains	2,199,000	2,530,000
Gross Unrealized (Losses)	(56,000)	0
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	68,014,000	53,216,000
CMOs issued by FHLMC
Debt Securities, Available-for-sale [Line Items]
Total	168,589,000	143,267,000
Available-for-sale, gross unrealized gains	5,525,000	7,925,000
Gross Unrealized (Losses)	(948,000)	(1,000)
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	173,166,000	151,191,000
CMOs issued by FNMA
Debt Securities, Available-for-sale [Line Items]
Total	21,663,000	16,450,000
Available-for-sale, gross unrealized gains	537,000	580,000
Gross Unrealized (Losses)	(31,000)	0
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	22,169,000	17,030,000
CMOs issued by GNMA
Debt Securities, Available-for-sale [Line Items]
Total	23,738,000	6,863,000
Available-for-sale, gross unrealized gains	236,000	351,000
Gross Unrealized (Losses)	0	0
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	23,974,000	7,214,000
SBA-backed securities
Debt Securities, Available-for-sale [Line Items]
Total	28,059,000	30,941,000
Available-for-sale, gross unrealized gains	1,212,000	1,976,000
Gross Unrealized (Losses)	(53,000)	(55,000)
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	29,218,000	32,862,000
Debentures of government- sponsored agencies
Debt Securities, Available-for-sale [Line Items]
Total	76,313,000	19,944,000
Available-for-sale, gross unrealized gains	201,000	266,000
Gross Unrealized (Losses)	(2,041,000)	(24,000)
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	74,473,000	20,186,000
Obligations of state and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Total	118,118,000	104,887,000
Available-for-sale, gross unrealized gains	3,842,000	5,765,000
Gross Unrealized (Losses)	(195,000)	0
Available-for-sale, allowance for credit Loss	0	0
Available-for-sale securities	121,765,000	$ 110,652,000
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Total	5,986,000
Available-for-sale, gross unrealized gains	0
Gross Unrealized (Losses)	(197,000)
Available-for-sale, allowance for credit Loss	0
Available-for-sale securities	$ 5,789,000

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