Investment Securities - Unrealized Loss Positions (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	$ 2,014	$ 81,958
Available-for-sale, greater than 12 continuous months, fair value	1,900	10,552
Available-for-sale, total securities in a loss position, fair value	3,914	92,510
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(1)	(328)
Available-for-sale, greater than 12 continuous months, unrealized loss	(57)	(83)
Available-for-sale, total securities in a loss position, unrealized loss	(58)	(411)
Marketable Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Marketable securities, less than 12 continuous months, fair value	2,014	96,161
Marketable securities, greater than 12 continuous months, fair value	1,900	18,350
Marketable securities, total securities in a loss position, fair value	3,914	114,511
Marketable Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Marketable securities, less than 12 continuous months, unrealized loss	(1)	(388)
Marketable securities, greater than 12 continuous months, unrealized loss	(57)	(172)
Marketable securities, total securities in a loss position, unrealized loss	(58)	(560)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months		14,203
Greater than or equal to 12 continuous months		7,798
Total Securities in a loss position		22,001
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months		(60)
Greater than or equal to 12 continuous months		(89)
Held-to-maturity, gross unrealized losses		(149)
MBS pass-through securities issued by FHLMC and FNMA
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value		4,367
Available-for-sale, greater than 12 continuous months, fair value		4,464
Available-for-sale, total securities in a loss position, fair value		8,831
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss		(34)
Available-for-sale, greater than 12 continuous months, unrealized loss		(14)
Available-for-sale, total securities in a loss position, unrealized loss		(48)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months		14,203
Greater than or equal to 12 continuous months		6,073
Total Securities in a loss position		20,276
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months		(60)
Greater than or equal to 12 continuous months		(84)
Held-to-maturity, gross unrealized losses		(144)
SBA-backed securities
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	0	9,227
Available-for-sale, greater than 12 continuous months, fair value	1,900	2,448
Available-for-sale, total securities in a loss position, fair value	1,900	11,675
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	0	(14)
Available-for-sale, greater than 12 continuous months, unrealized loss	(57)	(62)
Available-for-sale, total securities in a loss position, unrealized loss	(57)	(76)
CMOs issued by FHLMC
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	2,014	14,918
Available-for-sale, greater than 12 continuous months, fair value	0	2,981
Available-for-sale, total securities in a loss position, fair value	2,014	17,899
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(1)	(58)
Available-for-sale, greater than 12 continuous months, unrealized loss	0	(6)
Available-for-sale, total securities in a loss position, unrealized loss	$ (1)	(64)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months		0
Greater than or equal to 12 continuous months		1,725
Total Securities in a loss position		1,725
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months		0
Greater than or equal to 12 continuous months		(5)
Held-to-maturity, gross unrealized losses		(5)
CMOs issued by GNMA
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value		7,139
Available-for-sale, greater than 12 continuous months, fair value		0
Available-for-sale, total securities in a loss position, fair value		7,139
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss		(6)
Available-for-sale, greater than 12 continuous months, unrealized loss		0
Available-for-sale, total securities in a loss position, unrealized loss		(6)
Debentures of government- sponsored agencies
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value		25,228
Available-for-sale, greater than 12 continuous months, fair value		0
Available-for-sale, total securities in a loss position, fair value		25,228
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss		(70)
Available-for-sale, greater than 12 continuous months, unrealized loss		0
Available-for-sale, total securities in a loss position, unrealized loss		(70)
Obligations of state and political subdivisions
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value		20,579
Available-for-sale, greater than 12 continuous months, fair value		659
Available-for-sale, total securities in a loss position, fair value		21,238
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss		(145)
Available-for-sale, greater than 12 continuous months, unrealized loss		(1)
Available-for-sale, total securities in a loss position, unrealized loss		(146)
Corporate bonds
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value		500
Available-for-sale, greater than 12 continuous months, fair value		0
Available-for-sale, total securities in a loss position, fair value		500
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss		(1)
Available-for-sale, greater than 12 continuous months, unrealized loss		0
Available-for-sale, total securities in a loss position, unrealized loss		$ (1)

Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total

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Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value

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Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value

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Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss

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Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]

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Marketable Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for less than 12 months.

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