Significant Components of Contract Acquisition Costs, Net of Accumulated Amortization (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Conversion costs, net of accumulated amortization of $88.5 million and $109.8 million at 2012 and 2011, respectively	$ 89,055	$ 88,765
Payments for processing rights, net of accumulated amortization of $191.0 million and $186.1 million at 2012 and 2011, respectively	72,409	74,222
Total	$ 161,464	$ 162,987