Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning of year	$ 19,262	$ 15,904
Increases - tax positions taken in prior period	4,426	846
Decreases - tax positions taken in prior period	(124)
Increases - tax positions taken in current period	2,346	2,785
Settlement and lapse of statute of limitations		(273)
Unrecognized tax benefits, end of year	$ 25,910	$ 19,262