v2.4.0.8
Consolidated Statements of Comprehensive Income (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
Statement of Other Comprehensive Income [Abstract]                            
Net income $ 73,445 $ 62,188 [1] $ 54,048 [1] $ 63,998 [1] $ 80,991 [1] $ 56,145 $ 49,231 $ 46,706 $ 58,182 $ 233,759 $ 199,037 $ 261,225 $ 210,264 $ 169,071
Other comprehensive income (loss), net of tax:                            
Foreign currency translation 28,514   10,182             6,330 12,518 12,921 (4,273) 3,078
Net change in unrecognized gains (losses) on interest rate swaps, net of tax 625   (1,242)             3,986 (4,233) (3,201) (9,066) 8,712
Reversal of unrealized gain on pension plan, net of tax                       0 0 (15)
Total other comprehensive income (loss) 29,139   8,940             10,316 8,285 9,720 (13,339) 11,775
Total comprehensive income $ 102,584   $ 62,988             $ 244,075 $ 207,322 $ 270,945 $ 196,925 $ 180,846
[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."