Securities - Contractural Maturities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Securities Available-for-Sale, Amortized Cost
Due in one year or less	$ 413
Due after one year through five years	6,056
Due after five years through ten years	28,014
Due after ten years	209,115
Debt securities excluding securities not due at a single maturity date	243,598
Total	$ 428,439	$ 475,146
Securities Available-for-Sale, Weighted Average Yield
Due in one year or less (as a percent)	2.01%
Due after one year through five years (as a percent)	2.11%
Due after five years through ten years (as a percent)	2.31%
Due after ten years (as a percent)	3.03%
Debt securities (as a percent)	2.92%
Total (as a percent)	2.62%
Securities Available-for-Sale, Fair Value
Due in one year or less	$ 415
Due after one year through five years	6,309
Due after five years through ten years	28,993
Due after ten years	225,199
Debt securities	260,916
Fair Value	448,421	484,648
Collateralized Mortgage Obligations [Member]
Securities Available-for-Sale, Amortized Cost
Total	54,597	57,059
Securities Available-for-Sale, Fair Value
Fair Value	57,013	57,984
Asset-backed Securities [Member]
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	81,986
Total	$ 81,986	82,114
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	1.51%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 81,585
Fair Value	81,585	81,844
Collateralized loan obligations
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	31,202
Total	$ 31,202	66,898
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	2.12%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 30,688
Fair Value	30,688	$ 66,684
Mortgage-backed and collateralized mortgage obligations
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	$ 71,653
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	3.08%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 75,232