Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Due in one year or less, Amortized Cost	$ 26,009
Available-for-sale Securities, Due from one to five years, Amortized Cost	46,331
Available-for-sale Securities, Due from five to ten years, Amortized Cost	163,361
Available-for-sale Securities, Due after ten years, Amortized Cost	104,316
Available-for-sale Securities, Amortized Cost	1,478,635	$ 1,183,404
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract]
Held-to-maturity Securities, Due in one year or less, Amortized Cost	502
Held-to-maturity Securities, Due from one to five years, Amortized Cost	3,898
Held-to-maturity Securities, Amortized Cost	4,400	4,412
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Due in one year or less, Fair Value	26,278
Available-for-sale Securities, Due from one to five years, Fair Value	48,014
Available-for-sale Securities, Due from five to ten years, Fair Value	166,150
Available-for-sale Securities, Due after ten years, Fair Value	105,261
Available-for-sale Securities, Fair Value, Total	1,509,211	1,186,292
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract]
Held-to-maturity Securities, Due in one year or less, Fair Value	505
Held-to-maturity Securities, Due from one to five years, Fair Value	4,084
Held-to-maturity securities, Fair Value, Total	4,589	$ 4,498
Mortgage-Backed Securities
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Not due at single maturity, Amortized Cost	1,138,618
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Not due at single maturity, Fair Value	$ 1,163,508