CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 16,977	$ 23,421
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	8,167	7,973
Share-based compensation	7,235	5,832
Deferred income taxes	(1,576)	(1,418)
Tax effect from share-based payment arrangements	4,196	973
Excess tax benefits from share-based payment arrangements	(4,551)	(2,940)
Net amortization of premium on marketable securities		8
Provision for doubtful accounts, net	278	92
Net loss on sales of property and equipment		280
Changes in operating assets and liabilities:
Accounts receivable	2,755	6,754
Prepaid expenses and other assets	1,344	45
Accounts payable	1,848	1,748
Accrued compensation and employee benefits	(10,880)	(20,242)
Other liabilities	4,686	8,967
Deferred revenue	(2,101)	(2,764)
Net cash provided by operating activities	28,378	28,729
Cash flows from investing activities:
Purchases of property and equipment	(2,154)	(9,012)
Proceeds from maturities of marketable securities		22,000
Cash paid for acquisitions, net of cash acquired		(27,605)
Distribution from cost method investees		50
Net cash used in investing activities	(2,154)	(14,567)
Cash flows from financing activities:
Proceeds from revolving line of credit	8,000
Payments on other short-term loans		(2,933)
Proceeds from issuance of treasury stock under employee stock plans	2,011	6,189
Dividends paid	(694)	(702)
Repurchases of common stock	(27,125)
Excess tax benefits from share-based payment arrangements	4,551	2,940
Net cash provided by (used in) financing activities	(13,257)	5,494
Effect of exchange rate changes on cash	(208)	(426)
Increase in cash and cash equivalents	12,759	19,230
Cash and cash equivalents, beginning of period	83,178	71,609
Cash and cash equivalents, end of period	95,937	90,839
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds	1,285	1,978
Cash paid for interest	7,472	9,011
Supplemental disclosures of non-cash investing and financing activities:
Purchase of property and equipment included in accounts payable	$ 521	$ 1,045