Investment Securities (Narrative) (Details) $ in Millions	Sep. 30, 2019 USD ($) Investments	Dec. 31, 2018 Investments
Investment Securities (Textual)
Fair market value, less than 12 months, number of investments | Investments	24	8
Fair market value, less than 12 months | $	$ 27.8
Fair market value, 12 months or longer, number of investments | Investments	22
Fair market value, 12 months or longer | $	$ 20.0