Stockholders' Equity (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended		0 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Aug. 17, 2012 Common Class A [Member]	Aug. 19, 2011 Common Class A [Member]	Aug. 17, 2012 Common Class B [Member]	Aug. 19, 2011 Common Class B [Member]
Class of Stock [Line Items]
Maximum dividend payment which may be paid without prior approval from Colorado Division of Insurance	$ 91.9
Common stock, dividends paid (in dollars per share)	$ 0	$ 0
Common stock, dividends declared (in dollars per share)			$ 0.36	$ 0.36	$ 0.18	$ 0.18