Consolidated Statements Of Income (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue:
Finance charges	$ 538.2	$ 460.6	$ 388.0
Premiums earned	47.1	40.0	32.7
Other income	23.9	24.6	21.4
Total revenue	609.2	525.2	442.1
Costs and expenses:
Salaries and wages	82.2	63.0	61.3
General and administrative	30.5	25.6	26.4
Sales and marketing	31.2	23.6	19.7
Provision for credit losses	24.0	29.0	10.0
Interest	63.4	57.2	47.8
Provision for claims	34.8	30.4	23.4
Total costs and expenses	266.1	228.8	188.6
Income before provision for income taxes	343.1	296.4	253.5
Provision for income taxes	123.4	108.4	83.4
Net income	$ 219.7	$ 188.0	$ 170.1
Net income per share:
Basic	$ 8.65	$ 7.15	$ 5.79
Diluted	$ 8.58	$ 7.07	$ 5.67
Weighted average shares outstanding:
Basic	25,409,655	26,302,289	29,393,309
Diluted	25,598,956	26,600,855	29,984,819