Business Combinations (Details of Intangible Assets Acquired) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended
	Jul. 03, 2011 GlobalExpense	Jul. 03, 2011 GlobalExpense Software Technology	Jul. 03, 2011 GlobalExpense User base	Jul. 03, 2011 GlobalExpense Trademark and trade name	Jan. 24, 2011 Tripit	Jan. 24, 2011 Tripit Software Technology	Jan. 24, 2011 Tripit User base	Jan. 24, 2011 Tripit Trademark and trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 10,350	$ 3,570	$ 6,600	$ 180	$ 19,604	$ 8,980	$ 8,524	$ 2,100
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life		2 years	9 years	2 years		5 years	5 years	10 years