Share-based Compensation (Share-based Compensation Recorded in Income Statements) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation	$ 19,587	$ 13,718	$ 50,076	$ 31,447
Cost of operations
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation	3,509	1,492	9,573	4,061
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation	8,443	6,545	23,123	14,985
Systems development and programming
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation	2,464	1,643	6,476	3,607
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation	$ 5,171	$ 4,038	$ 10,904	$ 8,794