Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) claim	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Letters of credit outstanding	$ 235,700		$ 249,700
Surety bonds outstanding	$ 1,600,000		1,500,000
Maximum product warranty in years	10 years
Number of individual claims managed | claim	1,000
Self-insurance liabilities	$ 653,068	$ 719,172	641,779	$ 709,798
Adjustments to previously recorded reserves	(6,082)	1,300
ROU assets	69,000		71,300
Operating lease liabilities	88,331		91,400
Additional ROU assets under operating leases	1,100	9,600
Payments on lease liabilities	5,300	5,900
Total lease expense	10,200	9,900
Variable lease costs	1,900	1,900
Short-term lease costs	2,900	$ 2,200
Other Assets
Loss Contingencies [Line Items]
Recorded insurance receivables	$ 73,800		$ 69,500