Investment Securities - Unrealized Loss Positions (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	$ 137,582	$ 9,918
Available-for-sale, greater than 12 continuous months, fair value	1,699	1,790
Available-for-sale, total securities in a loss position, fair value	139,281	11,708
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(3,468)	(25)
Available-for-sale, greater than 12 continuous months, unrealized loss	(53)	(55)
Available-for-sale, total securities in a loss position, unrealized loss	(3,521)	(80)
Marketable Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Marketable securities, less than 12 continuous months, fair value	141,817	9,918
Marketable securities, greater than 12 continuous months, fair value	1,699	1,790
Marketable securities, total securities in a loss position, fair value	143,516	11,708
Marketable Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Marketable securities, less than 12 continuous months, unrealized loss	(3,657)	(25)
Marketable securities, greater than 12 continuous months, unrealized loss	(53)	(55)
Marketable securities, total securities in a loss position, unrealized loss	(3,710)	(80)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months	4,235
Greater than or equal to 12 continuous months	0
Total Securities in a loss position	4,235
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months	(189)
Greater than or equal to 12 continuous months	0
Held-to-maturity, gross unrealized losses	(189)
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	10,013
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	10,013
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(56)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(56)
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	0
Available-for-sale, greater than 12 continuous months, fair value	1,699	1,790
Available-for-sale, total securities in a loss position, fair value	1,699	1,790
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	0	0
Available-for-sale, greater than 12 continuous months, unrealized loss	(53)	(55)
Available-for-sale, total securities in a loss position, unrealized loss	(53)	(55)
CMOs issued by FNMA
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	7,304
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	7,304
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(31)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(31)
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	32,658	5,975
Available-for-sale, greater than 12 continuous months, fair value	0	0
Available-for-sale, total securities in a loss position, fair value	32,658	5,975
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(948)	(1)
Available-for-sale, greater than 12 continuous months, unrealized loss	0	0
Available-for-sale, total securities in a loss position, unrealized loss	(948)	(1)
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months	4,235
Greater than or equal to 12 continuous months	0
Total Securities in a loss position	4,235
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months	(189)
Greater than or equal to 12 continuous months	0
Held-to-maturity, gross unrealized losses	(189)
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	53,289	3,943
Available-for-sale, greater than 12 continuous months, fair value	0	0
Available-for-sale, total securities in a loss position, fair value	53,289	3,943
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(2,041)	(24)
Available-for-sale, greater than 12 continuous months, unrealized loss	0	0
Available-for-sale, total securities in a loss position, unrealized loss	(2,041)	$ (24)
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	28,529
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	28,529
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(195)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(195)
Corporate bonds
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	5,789
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	5,789
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(197)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	$ (197)

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, 12 Months or Longer, Accumulated Loss

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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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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 less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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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 unrealized loss position without allowance for credit loss.

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.

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

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