Securities - Unrealized Gains (Losses) of Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Total unrealized gains/(losses) on debt securities available-for-sale, Gross Unrealized Gains	$ 21,392	$ 33,478
Total unrealized gains/(losses) on debt securities available-for-sale, Gross Unrealized Losses	(3,070)	(90)
Total unrealized gains/(losses) on debt securities available-for-sale, Net Unrealized Gains/(Losses)	18,322	33,388
Income tax (expense) benefit, Gross Unrealized Gains	(4,569)	(7,128)
Income tax (expense) benefit, Gross Unrealized Losses	657	19
Income tax (expense) benefit, Net Unrealized Gains/(Losses)	(3,912)	(7,109)
Net Unrealized Gains/(Losses), Net of Tax Included in Accumulated Other Comprehensive Income/(Loss), Gross Unrealized Gains	16,823	26,350
Net Unrealized Gains/(Losses), Net of Tax Included in Accumulated Other Comprehensive Income/(Loss), Gross Unrealized Losses	(2,413)	(71)
Net Unrealized Gains/(Losses), Net of Tax Included in Accumulated Other Comprehensive Income/(Loss), Net Unrealized Gains/(Losses)	$ 14,410	$ 26,279