Investment Securities Summary of Gains and Losses from Equity and Debt Securities, and Losses from Other-than-Temporary Impairment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Equity Securities, FV-NI, Realized Gain		$ 9	$ 13,558
Debt and Equity Securities, Realized Gain (Loss)	$ 4,733	37	9,071
Debt Securities, Available-for-sale, Realized Gain (Loss)	4,733	28	(4,487)
Debt And Equity Securities, Realized Gain	11,554	1,665	13,873
Equity Securities, FV-NI, Realized Gain (Loss)		9	13,558
Debt Securities, Available-for-sale, Realized Gain	11,554	1,656	315
Equity Securities, FV-NI, Realized Loss		0	0
Debt Securities, Available-for-sale, Realized Loss	(6,821)	(1,628)	(4,802)
Debt And Equity Securities, Realized Loss	$ (6,821)	$ (1,628)	$ (4,802)