Accrued Expenses And Other Current Liabilities (Schedule of Reconciliation of the Activity Related to Accrued Warranty) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement in Standard and Extended Product Warranty, Increase (Decrease)
Balance at beginning of period	$ 32,393	$ 26,204	$ 21,641
Provision for warranty expense	25,399	20,985	17,267
Warranty liability from acquired businesses	150	125	240
Warranty costs paid	(19,440)	(14,921)	(12,944)
Balance at end of period	38,502	32,393	26,204
Less long-term portion	15,447	12,000	9,184
Current portion of accrued warranty	$ 23,055	$ 20,393	$ 17,020