Securities - Securities Available-for-sale and Held-to-maturity by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Securities held-to-maturity, amortized cost, due after ten years	$ 50,480
Securities held-to-maturity, fair value, due after ten years	52,532
Securities held-to-maturity, amortized cost	58,404	$ 58,888
Securities held-to-maturity, fair value	61,658	62,112
Securities available for sale, amortized cost, due after one years through five years	45,000
Securities available for sale, fair value, due after one years through five years	43,154
Securities available for sale, amortized cost, due after five years through ten years	102,927
Securities available for sale, fair value, due after five years through ten years	94,656
Securities available for sale, amortized cost, due after ten years	87,217
Securities available for sale, fair value, due after ten years	82,354
Securities available for sale, amortized cost, total other securities	679,250	778,294
Securities available for sale, fair value, total other securities	675,310	772,500
Other Debt Obligations [Member]
Securities held-to-maturity, amortized cost	50,480	50,954
Securities held-to-maturity, fair value	52,532	53,998
Securities available for sale, fair value, total other securities	232,803	248,651
Total Other Securities [Member]
Securities available for sale, amortized cost, total other securities	235,144
Securities available for sale, fair value, total other securities	220,164
Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	7,924	7,934
Securities held-to-maturity, fair value	9,126	8,114
Securities available for sale, amortized cost, total other securities	431,467	521,600
Securities available for sale, fair value, total other securities	442,507	523,849
Mutual Fund Debt Securities [Member]
Securities available for sale, amortized cost, total other securities	12,639	12,216
Securities available for sale, fair value, total other securities	$ 12,639	$ 12,216

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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