v2.4.0.8
Schedule of Revenue by Geographic Area (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2013
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets                            
Revenue $ 1,298,094 $ 1,067,915 [1] $ 1,016,707 [1] $ 1,006,531 [1] $ 1,031,777 [1] $ 939,632 $ 783,898 $ 759,684 $ 786,648 $ 3,745,839 $ 3,055,015 $ 4,122,930 $ 3,269,862 $ 2,469,881
United States
                            
Revenues from External Customers and Long-Lived Assets                            
Revenue 868,052   784,270             2,672,545 2,394,581 3,209,024 2,952,620 2,366,224
United Kingdom
                            
Revenues from External Customers and Long-Lived Assets                            
Revenue 266,384   181,383             708,089 507,272 696,072 138,486  
Other countries
                            
Revenues from External Customers and Long-Lived Assets                            
Revenue $ 163,658   $ 51,054             $ 365,205 $ 153,162 $ 217,834 $ 178,756 $ 103,657
[1] Gross margin and operating income during the quarters ended March 31, 2012, June 30, 2012, September 30, 2012 and December 31, 2012 include gains of $8.3 million, $8.4 million, $0.5 million and $0.7 million, respectively, resulting from lawsuit settlements with certain of our aftermarket product suppliers as discussed in Note 8, "Commitments and Contingencies."