Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract]
Held to maturity, amortized cost, total	$ 261,369	$ 357,949
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]
Held to maturity, fair value, total	262,213	349,895
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Available for sale, amortized cost, total	940,765	882,872
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale, fair value, total	946,855	865,831
Other debt obligations
Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract]
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
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]
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
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Available for sale, amortized cost, due in less than one year	3,472
Available for sale, amortized cost, due after one year through five years	8,582
Available for sale, amortized cost, due after five years through ten years	10,488
Available for sale, amortized cost, due after ten years	17,920
Available for sale, amortized cost, total	40,462
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale, fair value, due in less than one year	3,523
Available for sale, fair value, due after one year through five years	8,698
Available for sale, fair value, due after five years through ten years	10,979
Available for sale, fair value, due after ten years	18,669
Available for sale, fair value, total	41,869
Mortgage-backed securities and collateralized mortgage obligations of U.S. government sponsored entities
Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract]
Held to maturity, amortized cost, total	261,369
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]
Held to maturity, fair value, total	262,213	297,099
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Available for sale, amortized cost, total	604,934	567,753
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale, fair value, total	609,207	554,006
Private mortgage-backed securities and collateralized mortgage obligations
Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract]
Held to maturity, amortized cost, total	0
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]
Held to maturity, fair value, total	0	21,673
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Available for sale, amortized cost, total	56,005	55,569
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale, fair value, total	57,561	55,728
Collateralized loan obligations
Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract]
Held to maturity, amortized cost, total	0
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]
Held to maturity, fair value, total	0	31,123
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
Available for sale, amortized cost, total	239,364	212,807
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale, fair value, total	$ 238,218	$ 209,366