CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net income	$ 106,112	$ 45,226
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	27,621	20,649
Gain on settlement of equity method investment		(1,847)
Stock-based compensation	14,999	11,081
Amortization of premium on marketable securities and deferred financing costs	565	24
Earnings of equity method investments	(4,931)	(7,249)
Loss recovery on insurance claim	(1,103)
Deferred income tax benefit	(48,274)	498
Other gains on disposals of assets		(106)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(32,887)	(14,644)
Inventories	(21,647)	(12,851)
Prepaid expenses and other current assets	(4,395)	(6,076)
Accounts payable	16,656	9,470
Deferred revenue	487	17,875
Accrued warranty and retrofit costs	(192)	1,299
Accrued compensation and tax withholdings	(1,252)	279
Accrued restructuring costs	(1,523)	(4,201)
Accrued expenses and other current liabilities	(7,478)	1,954
Net cash provided by operating activities	42,758	61,381
Cash flows from investing activities
Purchases of property, plant and equipment	(9,320)	(6,827)
Purchases of marketable securities	(58,312)	(240)
Sales and maturities of marketable securities	8,450	3,590
Acquisitions, net of cash acquired	(82,977)	(5,346)
Purchases of other investments		(170)
Proceeds from sales of property, plant and equipment	200
Net cash used in investing activities	(141,959)	(8,993)
Cash flows from financing activities
Proceeds from term loan	197,554
Proceeds from issuance of common stock	1,395	960
Payment of deferred financing costs	(318)	(27)
Repayment of term loan	(1,000)
Common stock dividends paid	(21,202)	(20,932)
Net cash provided by (used in) financing activities	176,429	(19,999)
Effects of exchange rate changes on cash and cash equivalents	526	(394)
Net increase in cash and cash equivalents	77,754	31,995
Cash and cash equivalents, beginning of period	101,622	85,086
Cash and cash equivalents, end of period	179,376	117,081
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property, plant and equipment included in accounts payable	$ 1,418	1,009
Fair value of non-cash consideration for the acquisition of Cool Lab, LLC		$ 10,348