Securities, Amortized Cost and Fair Value Securities Available for Sale Contractual Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Maturing within one year	$ 18,967
Maturing after one year but within five years	80,229
Maturing after five years but within ten years	63,308
Maturing after ten years	160,956
Amortized cost	323,460
U.S. agency residential mortgage-backed	330,914
U.S. agency commercial mortgage-backed	8,039
Private label mortgage-backed	43,190
Other asset backed	262,435
Amortized cost	968,038	$ 513,668
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Maturing within one year	19,048
Maturing after one year but within five years	83,042
Maturing after five years but within ten years	66,592
Maturing after ten years	164,731
Total available-for-sale securities fair value	333,413
U.S. agency residential mortgage-backed	335,560
U.S. agency commercial mortgage-backed	8,421
Private label mortgage-backed	44,285
Other asset backed	263,371
Total	$ 985,050	$ 518,400