CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Accounts receivable, reserve for credit losses	$ 13,163	$ 10,396
Property, equipment and capitalized software, accumulated depreciation	$ 152,380	$ 145,400
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	175,000,000	175,000,000
Common stock, shares issued	42,971,000	42,901,000
Common stock, shares outstanding	38,877,000	38,987,000
Treasury stock, shares	4,188,000	4,007,000