Shareholders' Equity, Dividends & Stock Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended					1 Months Ended	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 DriveTime Automotive Group, Inc [Member]	Dec. 31, 2012 DriveTime Automotive Group, Inc [Member]	Mar. 31, 2013 DT Acceptance Corp [Member]	Dec. 31, 2012 DT Acceptance Corp [Member]	Apr. 30, 2013 Subsequent Event [Member]	Mar. 31, 2013 Chief Executive Officer [Member] Restricted Stock [Member]	Mar. 31, 2012 Chief Executive Officer [Member] Restricted Stock [Member]
Dividends Payable [Line Items]
Par value of common stock			$ 0.001		$ 0
Shares of common stock authorized			1,000		1,000,000
Shares of common stock issued		101.8		101.8
Shares of common stock outstanding		101.8		101.8
Dividends, percentage of the difference between net earnings and amounts paid for tax that may be included in dividends paid	50.00%
Payments of cash dividends						$ 10.9
Restricted stock compensation expense							$ 0.3	$ 0.5