Segment Information (Details 1) (USD $)

3 Months Ended

12 Months Ended

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

Segment Income Loss From Continuing Operations Before Provision For Income Tax [Line Items]

Income before income taxes

$ 321,089,000

$ 201,479,000

$ 215,892,000

$ 180,763,000

$ 193,251,000

$ 156,396,000

$ 187,169,000

$ 226,755,000

$ 919,223,000

$ 763,571,000

$ 806,181,000

US Segment Reporting Information [Member]

Segment Income Loss From Continuing Operations Before Provision For Income Tax [Line Items]

Income before income taxes

636,410,000

425,637,000

526,127,000

Canada Segment Reporting Information [Member]

Segment Income Loss From Continuing Operations Before Provision For Income Tax [Line Items]

Income before income taxes

186,971,000

164,953,000

121,738,000

Europe And South Africa Segment Reporting Information [Member]

Segment Income Loss From Continuing Operations Before Provision For Income Tax [Line Items]

Income before income taxes

73,947,000

83,102,000

72,125,000

Asia Pacific Segment Reporting Information [Member]

Segment Income Loss From Continuing Operations Before Provision For Income Tax [Line Items]

Income before income taxes

45,378,000

42,234,000

73,882,000

Corporate And Other Segment Reporting Information [Member]

Segment Income Loss From Continuing Operations Before Provision For Income Tax [Line Items]

Income before income taxes

$ (23,483,000)

$ 47,645,000

$ 12,309,000