v2.4.0.8

Basis of Presentation - Effects of Prior Period Errors in Consolidated Statement of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended
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Dec. 31, 2012 | Sep. 30, 2012 | Jun. 30, 2012 | Mar. 31, 2012 | Dec. 31, 2011 | Sep. 30, 2011 | Jun. 30, 2011 | Mar. 31, 2011 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2012 As Previously Reported [Member] | Sep. 30, 2012 As Previously Reported [Member] | Jun. 30, 2012 As Previously Reported [Member] | Mar. 31, 2012 As Previously Reported [Member] | Dec. 30, 2011 As Previously Reported [Member] | Sep. 30, 2011 As Previously Reported [Member] | Jun. 30, 2011 As Previously Reported [Member] | Mar. 31, 2011 As Previously Reported [Member] | Dec. 31, 2012 As Previously Reported [Member] | Dec. 31, 2011 As Previously Reported [Member] | Dec. 31, 2010 As Previously Reported [Member] | Dec. 31, 2012 As Adjusted [Member] | Sep. 30, 2012 As Adjusted [Member] | Jun. 30, 2012 As Adjusted [Member] | Mar. 31, 2012 As Adjusted [Member] | Dec. 31, 2011 As Adjusted [Member] | Sep. 30, 2011 As Adjusted [Member] | Jun. 30, 2011 As Adjusted [Member] | Mar. 31, 2011 As Adjusted [Member] | Dec. 31, 2012 As Adjusted [Member] | Dec. 31, 2011 As Adjusted [Member] | Dec. 31, 2010 As Adjusted [Member]
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income | $ 112,200 | $ 111,900 | $ 132,000 | $ 107,900 | $ 110,100 | $ 107,500 | $ 108,600 | $ 88,800 | $ 463,962 | $ 414,959 | $ 292,883 | $ 117,881 | $ 117,779 | $ 133,368 | $ 108,162 | $ 105,357 | $ 108,022 | $ 111,180 | $ 88,019 | $ 477,190 | $ 412,578 | $ 299,215 | $ 112,207 | $ 111,873 | $ 131,951 | $ 107,931 | $ 110,072 | $ 107,459 | $ 108,601 | $ 88,827 | $ 463,962 | $ 414,959 | $ 292,883
Excess tax benefits from share-based payment arrangements |  |  |  |  |  |  |  |  | (29,684) | (26,241) | (8,937) |  |  |  |  |  |  |  |  | (29,684) | (27,450) | (7,728) |  |  |  |  |  |  |  |  | (29,684) | (26,241) | (8,937)
Deferred income taxes |  |  |  |  |  |  |  |  | (7,758) | (21,271) | (33,338) |  |  |  |  |  |  |  |  | (9,050) | (12,984) | (33,313) |  |  |  |  |  |  |  |  | (7,758) | (21,271) | (33,338)
Income taxes |  |  |  |  |  |  |  |  | 28,042 | 48,565 | (2,450) |  |  |  |  |  |  |  |  | 16,106 | 42,659 | (8,807) |  |  |  |  |  |  |  |  | 28,042 | 48,565 | (2,450)
Net cash provided by operating activities |  |  |  |  |  |  |  |  | 567,784 | 510,540 | 387,875 |  |  |  |  |  |  |  |  | 567,784 | 509,331 | 389,084 |  |  |  |  |  |  |  |  | 567,784 | 510,540 | 387,875
Excess tax benefits from share-based payment arrangements |  |  |  |  |  |  |  |  | 29,684 | 26,241 | 8,937 |  |  |  |  |  |  |  |  | 29,684 | 27,450 | 7,728 |  |  |  |  |  |  |  |  | 29,684 | 26,241 | 8,937
Net cash used in financing activities |  |  |  |  |  |  |  |  | $ (371,241) | $ (339,008) | $ (261,953) |  |  |  |  |  |  |  |  | $ (371,241) | $ (337,799) | $ (263,162) |  |  |  |  |  |  |  |  | $ (371,241) | $ (339,008) | $ (261,953)

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