Other Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Software systems development costs, net
Other assets
Other assets	$ 74,100	$ 62,054
Capitalized costs during year	30,800	26,900
Amortization expense for period	24,000	27,000	28,200
Deferred financing costs
Other assets
Other assets	33,918	31,151
Capitalized costs during period	14,500	12,700	14,700
Amortization expense for period	7,500	6,500	5,100
Deferred tax asset, long-term portion
Other assets
Other assets	11,217	15,580
Other assets
Other assets
Other assets	$ 13,394	$ 22,799