Investments (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Gain on available-for-sale investments	$ 7,716	$ 549	$ 90
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Realized Gains	7,600
Tax on gain/loss on Sale of Investments	$ 2,900