Securities - Unrealized Gains (Losses) of Debt Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Total unrealized gains/(losses) on debt securities available-for-sale, Gross Unrealized Gains	$ 5,962	$ 3,514
Total unrealized gains/(losses) on debt securities available-for-sale, Gross Unrealized Losses	(3,678)	(8,628)
Total unrealized gains/(losses) on debt securities available-for-sale, Net Unrealized (Losses)/Gains	2,284	(5,114)
Income tax (expense) benefit, Gross Unrealized Gains	(1,271)	(746)
Income tax (expense) benefit, Gross Unrealized Losses	784	1,832
Income tax (expense) benefit, Net Unrealized (Losses)/Gains	(487)	1,086
Net Unrealized (Losses)/Gains, Net of Tax Included in Accumulated Other Comprehensive Loss, Gross Unrealized Gains	4,691	2,768
Net Unrealized (Losses)/Gains, Net of Tax Included in Accumulated Other Comprehensive Loss, Gross Unrealized Losses	(2,894)	(6,796)
Net Unrealized (Losses)/Gains, Net of Tax Included in Accumulated Other Comprehensive Loss, Net Unrealized (Losses)/Gains	$ 1,797	$ (4,028)