Revision To Previously Reported Financial Information ( Correction Of Immaterial Error On Impacted Line Items Of The Consolidated Balance Sheet) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Current portion notes receivable	$ 26,558	$ 28,397	[1]
Total current assets	677,503	790,982	[1]
Notes receivable, net of current portion	83,370	76,539	[1]
Total assets	2,326,519	2,405,488	[1]
Deferred income taxes		1,072	[1]
Total current liabilities	446,086	286,302	[1]
Deferred income taxes	96,801	85,956	[1]
Total liabilities	1,274,750	1,237,882	[1]
Additional paid-in capital	365,746	546,336	[1]
Retained earnings	738,321	674,299	[1]
Total stockholders' equity	1,051,769	1,167,606	[1]
Total liabilities and stockholders' equity	2,326,519	2,405,488	[1]
Immaterial Error Correction [Member] | As Reported [Member]
Current portion notes receivable		26,130
Total current assets		788,715
Notes receivable, net of current portion		87,677
Total assets		2,414,359
Deferred income taxes		4,052
Total current liabilities		289,282
Deferred income taxes		92,134
Total liabilities		1,247,040
Additional paid-in capital		532,929
Retained earnings		687,419
Total stockholders' equity		1,167,319
Total liabilities and stockholders' equity		2,414,359
Immaterial Error Correction [Member] | As Revised [Member]
Current portion notes receivable		28,397
Total current assets		790,892
Notes receivable, net of current portion		76,539
Total assets		2,405,488
Deferred income taxes		1,072
Total current liabilities		286,302
Deferred income taxes		85,956
Total liabilities		1,237,882
Additional paid-in capital		546,336
Retained earnings		674,299
Total stockholders' equity		1,167,606
Total liabilities and stockholders' equity		$ 2,405,488

[1] As Revised (Note 2)