Comprehensive Income and Capital Structure (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Stockholders Equity, Opening Balance			$ 883,116
Issuance of common stock upon exercise of stock options or RSU release, net of shares withheld for taxes			$ 20,214
Issuance of common stock upon exercise of stock options or RSU release, net of shares withheld for taxes (Shares)			866,457
Issuance of common stock in connection with RSG acquisition			$ 306,825
Stock-based compensation			14,070	$ 7,305
Other comprehensive income	$ 365	$ 1,126	2,122	(8,529)
Net income	41,126	28,349	42,525	31,470
Stockholders Equity, Ending Balance	1,269,650	$ 852,454	1,269,650	$ 852,454
Common Stock
Stockholders Equity, Opening Balance			$ 497
Stockholders Equity, Opening Balance (Shares)			49,790,743
Issuance of common stock upon exercise of stock options or RSU release, net of shares withheld for taxes			$ 9
Issuance of common stock upon exercise of stock options or RSU release, net of shares withheld for taxes (Shares)			878,245
Issuance of common stock in connection with RSG acquisition			$ 91
Issuance of common stock in connection with RSG acquisition (Shares)			9,039,008
Stock-based compensation			$ 0
Other comprehensive income			0
Net income			0
Stockholders Equity, Ending Balance	$ 597		$ 597
Stockholders Equity, Ending Balance (Shares)	59,707,996		59,707,996
Additional Paid-in Capital
Stockholders Equity, Opening Balance			$ 345,934
Issuance of common stock upon exercise of stock options or RSU release, net of shares withheld for taxes			20,205
Issuance of common stock in connection with RSG acquisition			306,734
Stock-based compensation			14,070
Other comprehensive income			0
Net income			0
Stockholders Equity, Ending Balance	$ 686,943		686,943
Retained Earnings
Stockholders Equity, Opening Balance			557,405
Issuance of common stock upon exercise of stock options or RSU release, net of shares withheld for taxes			0
Issuance of common stock in connection with RSG acquisition			0
Stock-based compensation			0
Other comprehensive income			0
Net income			42,525
Stockholders Equity, Ending Balance	599,930		599,930
Accumulated Other Comprehensive Income (Loss)
Stockholders Equity, Opening Balance			(20,720)
Issuance of common stock upon exercise of stock options or RSU release, net of shares withheld for taxes			0
Issuance of common stock in connection with RSG acquisition			0
Stock-based compensation			0
Other comprehensive income			2,900
Net income			0
Stockholders Equity, Ending Balance	$ (17,820)		$ (17,820)