Commitments And Contingencies Product Warranty Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Product Warranties Disclosures [Abstract]
Balance at the beginning of the period	$ 58,520	$ 56,706	$ 44,888
Standard and Extended Product Warranty Accrual, Increase for Warranties Issued	131,263	87,570	80,085
Settlements made during the year	(113,959)	(85,756)	(68,267)
Balance at the end of the period	$ 75,824	$ 58,520	$ 56,706