Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2007 California Franchise Tax Board [Member]	Dec. 31, 2006 California Franchise Tax Board [Member]	Dec. 31, 2005 California Franchise Tax Board [Member]	Dec. 31, 2010 Internal Revenue Service (IRS) [Member]	Dec. 31, 2009 Internal Revenue Service (IRS) [Member]	Dec. 31, 2010 Canada Revenue Agency [Member]	Dec. 31, 2009 Canada Revenue Agency [Member]	Dec. 31, 2008 Canada Revenue Agency [Member]
Income Taxes [Line Items]
U.S. federal statutory rate	35.00%
Effective income tax rate	19.50%
Income before income taxes, domestic operations	$ 5.4	$ 13.8
Income before income taxes, foreign operations	22.9	23.1
Liabilities for uncertain income tax positions	39.0		37.7
Cash paid for income taxes	3.5
Prepaid tax payments	$ 7.4		$ 9.0
Income Tax Examination, Year under Examination				2007	2006	2005	2010	2009	2010	2009	2008