Debt Schedule Of Components Of Debt (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Senior Notes [Member]	Sep. 30, 2012 Senior Notes [Member] 400 Million Senior Notes [Member]	Jun. 27, 2012 Senior Notes [Member] 400 Million Senior Notes [Member]	Dec. 31, 2011 Senior Notes [Member] 400 Million Senior Notes [Member]	Sep. 30, 2012 Senior Notes [Member] 250 Million Senior Notes [Member]	Dec. 31, 2011 Senior Notes [Member] 250 Million Senior Notes [Member]	Aug. 25, 2010 Senior Notes [Member] 250 Million Senior Notes [Member]	Sep. 30, 2012 Senior Secured Credit Facility [Member]	Sep. 30, 2012 Senior Secured Credit Facility [Member] 350 Million Senior Secured Credit Facility [Member]	Jul. 25, 2012 Senior Secured Credit Facility [Member] 350 Million Senior Secured Credit Facility [Member]	Dec. 31, 2011 Senior Secured Credit Facility [Member] 350 Million Senior Secured Credit Facility [Member]	Sep. 30, 2012 Capital Lease Obligations [Member]	Dec. 31, 2011 Capital Lease Obligations [Member]	Sep. 30, 2012 Other Notes Payable [Member]	Dec. 31, 2011 Other Notes Payable [Member]
Total debt	$ 818,976,000	$ 252,705,000	$ 649,491,000	$ 400,000,000		$ 0	$ 249,491,000	$ 249,444,000		$ 166,725,000	$ 166,725,000		$ 0	$ 2,684,000	$ 3,172,000	$ 76,000	$ 89,000
Less current portion	(10,065,000)	(673,000)
Total long-term debt	808,911,000	252,032,000
Debt instrument face amount					400,000,000				250,000,000			350,000,000
Debt instruments effective interest rate				5.94%	5.94%		6.19%	6.19%	6.19%		2.82%			3.18%	3.18%
Senior notes, discount							$ 500,000	$ 600,000	$ 600,000
Capital Lease Maturity Year														2016	2016