Investment Securities Summary of Gains and Losses from Equity and Debt Securities, and Losses from Other-than-Temporary Impairment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gain (Loss) on Investments [Line Items]
Gross Realized Gains	$ 1,530	$ 1,450	$ 1,549	$ 2,556
Gross Realized Losses	(1,526)	(14)	(1,526)	(14)
Net Gains (Losses)	4	1,436	23	2,542
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Gross Realized Gains	0	1,305	9	2,350
Gross Realized Losses	0	0	0	0
Net Gains (Losses)	0	1,305	9	2,350
Debt Securities [Member]
Gain (Loss) on Investments [Line Items]
Gross Realized Gains	1,530	145	1,540	206
Gross Realized Losses	(1,526)	(14)	(1,526)	(14)
Net Gains (Losses)	$ 4	$ 131	$ 14	$ 192