Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Amortized Cost
Held to maturity, amortized cost, total	$ 638,640	$ 184,484
Fair Value
Held to maturity, fair value, total	627,398	192,179
Amortized Cost
Available for sale, amortized cost, total	1,653,658	1,371,539
Fair Value
Available for sale, fair value, total	1,644,319	1,398,157
Other debt
Amortized Cost
Held to maturity, amortized cost, due in less than one year	0
Held to maturity, amortized cost, due after one year through five years	0
Held to maturity, amortized cost, due after five years through ten years	0
Held to maturity, amortized cost, due after ten years	0
Held to maturity, amortized cost, total	0
Fair Value
Held to maturity, fair value, due in less than one year	0
Held to maturity, fair value, due after one year through five years	0
Held to maturity, fair value, due after five years through ten years	0
Held to maturity, fair value, due after ten years	0
Held to maturity, fair value, total	0
Amortized Cost
Available for sale, amortized cost, due in less than one year	2,174
Available for sale, amortized cost, due after one year through five years	14,017
Available for sale, amortized cost, due after five years through ten years	7,041
Available for sale, amortized cost, due after ten years	14,858
Available for sale, amortized cost, total	38,090
Fair Value
Available for sale, fair value, due in less than one year	2,210
Available for sale, fair value, due after one year through five years	14,841
Available for sale, fair value, due after five years through ten years	7,341
Available for sale, fair value, due after ten years	15,750
Available for sale, fair value, total	40,142
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities
Amortized Cost
Held to maturity, amortized cost, total	638,640
Fair Value
Held to maturity, fair value, total	627,398	192,179
Amortized Cost
Available for sale, amortized cost, total	1,234,721	1,038,437
Fair Value
Available for sale, fair value, total	1,222,720	1,060,654
Private mortgage-backed securities and collateralized mortgage obligations
Amortized Cost
Held to maturity, amortized cost, total	0
Fair Value
Held to maturity, fair value, total	0
Amortized Cost
Available for sale, amortized cost, total	88,096	89,284
Fair Value
Available for sale, fair value, total	88,767	91,205
Collateralized loan obligations
Amortized Cost
Held to maturity, amortized cost, total	0
Fair Value
Held to maturity, fair value, total	0
Amortized Cost
Available for sale, amortized cost, total	292,751	202,563
Fair Value
Available for sale, fair value, total	$ 292,690	$ 202,195