Investment Securities - Unrealized Loss Positions (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months	$ 36,588
Greater than or equal to 12 continuous months	0
Total Securities in a loss position	36,588
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months	(164)
Greater than or equal to 12 continuous months	0
Held-to-maturity, gross unrealized losses	(164)
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	359,280
Available-for-sale, greater than 12 continuous months, fair value	5,119
Available-for-sale, total securities in a loss position, fair value	364,399
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(3,397)
Available-for-sale, greater than 12 continuous months, unrealized loss	(199)
Available-for-sale, total securities in a loss position, unrealized loss	(3,596)
Marketable Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Marketable securities, less than 12 continuous months, fair value	395,868	$ 9,918
Marketable securities, greater than 12 continuous months, fair value	5,119	1,790
Marketable securities, total securities in a loss position, fair value	400,987	11,708
Marketable Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Marketable securities, less than 12 continuous months, unrealized loss	(3,561)	(25)
Marketable securities, greater than 12 continuous months, unrealized loss	(199)	(55)
Marketable securities, total securities in a loss position, unrealized loss	(3,760)	(80)
MBS pass-through securities issued by FHLMC and FNMA
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months	17,074
Greater than or equal to 12 continuous months	0
Total Securities in a loss position	17,074
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months	(38)
Greater than or equal to 12 continuous months	0
Held-to-maturity, gross unrealized losses	(38)
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	63,171
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	63,171
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(243)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(243)
CMOs issued by FHLMC
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months	9,320
Greater than or equal to 12 continuous months	0
Total Securities in a loss position	9,320
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months	(95)
Greater than or equal to 12 continuous months	0
Held-to-maturity, gross unrealized losses	(95)
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	142,557	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	142,557	5,975
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(1,065)	(1)
Available-for-sale, greater than 12 continuous months, unrealized loss	0	0
Available-for-sale, total securities in a loss position, unrealized loss	(1,065)	(1)
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	25,256
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	25,256
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(211)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(211)
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	25,879
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	25,879
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(249)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(249)
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	8,115	0
Available-for-sale, greater than 12 continuous months, fair value	1,307	1,790
Available-for-sale, total securities in a loss position, fair value	9,422	1,790
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(93)	0
Available-for-sale, greater than 12 continuous months, unrealized loss	(43)	(55)
Available-for-sale, total securities in a loss position, unrealized loss	(136)	(55)
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	50,344	3,943
Available-for-sale, greater than 12 continuous months, fair value	3,812	0
Available-for-sale, total securities in a loss position, fair value	54,156	3,943
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(1,021)	(24)
Available-for-sale, greater than 12 continuous months, unrealized loss	(156)	0
Available-for-sale, total securities in a loss position, unrealized loss	(1,177)	$ (24)
U.S. Treasury securities
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	11,777
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	11,777
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(104)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(104)
Obligations of state and political subdivisions
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 continuous months	10,194
Greater than or equal to 12 continuous months	0
Total Securities in a loss position	10,194
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 continuous months	(31)
Greater than or equal to 12 continuous months	0
Held-to-maturity, gross unrealized losses	(31)
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	16,494
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	16,494
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(169)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(169)
Corporate bonds
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	13,778
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	13,778
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(237)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	(237)
Asset-backed securities
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale, less than 12 continuous months, fair value	1,909
Available-for-sale, greater than 12 continuous months, fair value	0
Available-for-sale, total securities in a loss position, fair value	1,909
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Available-for-sale, less than 12 continuous months, unrealized loss	(5)
Available-for-sale, greater than 12 continuous months, unrealized loss	0
Available-for-sale, total securities in a loss position, unrealized loss	$ (5)

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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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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