Investment Securities and Equity Securities with Readily Determinable Fair Values (Unrealized and realized gains and losses recognized in net income on equity securities ) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Investment Securities and Equity Securities with Readily Determinable Fair Values
Equity Securities	$ 6,125		$ 6,095
Summary of unrealized and realized gains and losses recognized in net income on equity securities
Net gains (losses) recognized during the period on equity securities	30	$ 138
Unrealized gain on equity securities with readily determinable fair values	$ 30	$ 138