Derivatives (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Maximum length of time to hedge (in months)	12 months
Foreign exchange gross notional amount			$ 1,800,000
Unrealized loss on effective portion of foreign exchange forward contracts, net	$ 0	$ 0
After tax net unrealized loss recorded in accumulated other comprehensive loss reclassified to earnings		$ 147,000