Investment Securities, Available-for-sale Securities, Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Amortized Cost [Abstract]
Due in one year or less	$ 18,563
Due in one year through five years	81,445
Due after five years through ten years	18
Amortized Cost	444,115	$ 573,432
Fair Value [Abstract]
Due in one year or less	18,747
Due in one year through five years	82,140
Due after five years through ten years	18
Fair Value	454,743	573,823
Mortgage-Backed Securities and Collateralized Mortgage Obligations - Residential [Member]
Amortized Cost [Abstract]
Securities, amortized cost	301,490
Amortized Cost	301,490	388,537
Fair Value [Abstract]
Securities, fair value	309,768
Fair Value	309,768	389,517
Small Business Administration-Guaranteed Participation Securities [Member]
Amortized Cost [Abstract]
Securities, amortized cost	42,599
Amortized Cost	42,599	48,991
Fair Value [Abstract]
Securities, fair value	44,070
Fair Value	$ 44,070	$ 48,511

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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