Accrued and Other Liabilities (Schedule of Recognized Warranty Revenue and Incurred Warranty Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Warranty obligations [Roll Forward]
Beginning Balance	$ 10,202	$ 9,051	$ 10,663
Additional Accrual/ Revenue Deferred	9,347	13,623	12,859
Costs Incurred/ Deferred Revenue Amortization	(11,889)	(12,472)	(14,471)
Ending Balance	$ 7,660	$ 10,202	$ 9,051