CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income	$ 19,241	$ 14,407
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,441	8,107
Share-based compensation	14,700	8,794
Deferred income taxes	5,986	5,676
Tax effect from share-based payment arrangements	9,615	6,379
Excess tax benefits from share-based payment arrangements	(10,079)	(6,485)
Provision for doubtful accounts, net	438	0
Changes in operating assets and liabilities:
Accounts receivable	18,005	5,863
Prepaid expenses and other assets	(14,807)	(8,843)
Accounts payable	2,022	3,886
Accrued compensation and employee benefits	(16,381)	(26,046)
Other liabilities	(2,438)	(13,850)
Deferred revenue	6,807	3,472
Net cash provided by operating activities	40,550	1,360
Cash flows from investing activities:
Purchases of property and equipment	(4,294)	(5,667)
Distribution from cost method investees	0	75
Net cash used in investing activities	(4,294)	(5,592)
Cash flows from financing activities:
Proceeds from revolving line of credit	26,000	81,000
Payments on revolving line of credit	(15,000)	(20,000)
Proceeds from issuance of treasury stock under employee stock plans	1,199	6,713
Taxes paid related to net share settlement of equity awards	(24,462)	(15,007)
Dividends paid	(622)	(635)
Repurchases of common stock	(28,382)	(60,593)
Excess tax benefits from share-based payment arrangements	10,079	6,485
Net cash used in financing activities	(31,188)	(2,037)
Effect of exchange rate changes on cash	(478)	(4,155)
Increase (decrease) in cash and cash equivalents	4,590	(10,424)
Cash and cash equivalents, beginning of period	86,120	105,075
Cash and cash equivalents, end of period	90,710	94,651
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds	4,364	8,844
Cash paid for interest	5,823	7,539
Supplemental disclosures of non-cash investing and financing activities:
Purchase of property and equipment included in accounts payable	$ 267	$ 296