Long-Term Debt (Fair Value And Carrying Value Of Debt Instruments) (Details) (USD $) In Thousands, unless otherwise specified				0 Months Ended	12 Months Ended																								0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2013 3.85% Notes, Payable February 1, 2023 [Member]	Jan. 17, 2006 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2013 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2012 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2013 Five Year Senior Secured Credit Facility Due July 8, 2016	Dec. 31, 2012 Five Year Senior Secured Credit Facility Due July 8, 2016	Dec. 31, 2013 Fair Value [Member]	Dec. 31, 2012 Fair Value [Member]	Dec. 31, 2013 Fair Value [Member] 3.85% Notes, Payable February 1, 2023 [Member]	Dec. 31, 2012 Fair Value [Member] 3.85% Notes, Payable February 1, 2023 [Member]	Dec. 31, 2013 Fair Value [Member] 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2012 Fair Value [Member] 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2013 Fair Value [Member] Five Year Senior Secured Credit Facility Due July 8, 2016	Dec. 31, 2012 Fair Value [Member] Five Year Senior Secured Credit Facility Due July 8, 2016	Dec. 31, 2013 Fair Value [Member] Five Year Senior Secured Credit Facility Due September 25, 2018	Dec. 31, 2012 Fair Value [Member] Five Year Senior Secured Credit Facility Due September 25, 2018	Dec. 31, 2013 Carrying Value [Member]	Dec. 31, 2012 Carrying Value [Member]	Dec. 31, 2013 Carrying Value [Member] 3.85% Notes, Payable February 1, 2023 [Member]	Dec. 31, 2012 Carrying Value [Member] 3.85% Notes, Payable February 1, 2023 [Member]	Dec. 31, 2013 Carrying Value [Member] 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2012 Carrying Value [Member] 6.125% Notes, Payable January 15, 2016 [Member]	Dec. 31, 2013 Carrying Value [Member] Five Year Senior Secured Credit Facility Due July 8, 2016	Dec. 31, 2012 Carrying Value [Member] Five Year Senior Secured Credit Facility Due July 8, 2016	Dec. 31, 2013 Carrying Value [Member] Five Year Senior Secured Credit Facility Due September 25, 2018	Dec. 31, 2012 Carrying Value [Member] Five Year Senior Secured Credit Facility Due September 25, 2018	Dec. 19, 2012 Secured Credit Facility [Member]	Dec. 31, 2013 Secured Credit Facility [Member] Fair Value [Member]	Dec. 31, 2012 Secured Credit Facility [Member] Fair Value [Member]	Dec. 31, 2013 Secured Credit Facility [Member] Carrying Value [Member]	Dec. 31, 2012 Secured Credit Facility [Member] Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes payable											$ 569,400	$ 0	$ 983,700	$ 1,011,600	$ 0	$ 153,875	$ 364,005	$ 0			$ 600,000	$ 0	$ 900,000	$ 900,000	$ 0	$ 153,875	$ 364,005	$ 0
Securitization facility																														300,000	280,000	300,000	280,000
Industrial revenue bonds, capital leases and other									96,003	49,067									96,003	49,067
Total long-term debt									2,313,108	1,494,542									2,260,008	1,382,942
Current portion of long-term debt	127,218	55,213							127,218	55,213									127,218	55,213
Long-term debt, less current portion									$ 2,185,890	$ 1,439,329									$ 2,132,790	$ 1,327,729
Interest rate percentage			3.85%	6.125%	6.125%	6.125%
Notes payable, maturity date				Jan. 15, 2016	Jan. 15, 2016	Jan. 15, 2016	Jul. 08, 2016	Jul. 08, 2016
Term of line of credit (years)							5 years	5 years																					3 years