Commitments And Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2017 USD ($) claim	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) claim	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Operating lease rent expense			$ 30,800	$ 33,000	$ 27,700
Letters of credit outstanding, amount	$ 235,500	$ 219,100	235,500	219,100
Surety Bonds Outstanding	$ 1,200,000	1,100,000	$ 1,200,000	1,100,000
Charges related to contractual dispute				15,000	20,000
Maximum product warranty in years			10 years
Loss Contingency, Pending Claims, Number | claim	1,000		1,000
Self-insurance liabilities	$ 758,812	$ 831,058	$ 758,812	$ 831,058	924,563	$ 995,692
Incurred but not reported percentage of liability reserves	65.00%	70.00%	65.00%	70.00%
Adjustment to self insurance reserves	$ 75,300	$ 55,200	$ (95,100)	$ (55,200)	(62,200)
Increase (Decrease) in Self Insurance Reserve					$ (29,600)
Florida [Member]
Loss Contingencies [Line Items]
Product Warranty Expense			$ 12,400