CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Net income	$ 35,880	$ 25,090
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	49,760	40,429
Impairment of property, plant and equipment	301
Stock-based compensation	12,348	15,172
Amortization of premium on marketable securities and deferred financing costs	177	766
Earnings of equity method investments		(4,876)
Deferred income taxes	(9,319)	(9,207)
Loss on extinguishment of debt		9,051
Other losses on disposals of assets	163	156
Loss on sale of divestiture, net of tax	319
Taxes paid stemming from divestiture	(91,500)
Changes in operating assets and liabilities, net of acquisitions and divestiture:
Accounts receivable	(15,719)	(6,456)
Inventories	(17,695)	(6,431)
Prepaid expenses and other assets	12,554	2,109
Accounts payable	11,032	(6,761)
Deferred revenue	214	4,959
Accrued warranty and retrofit costs	580	1,022
Accrued compensation and tax withholdings	1,928	(9,404)
Accrued restructuring costs	(609)	(361)
Proceeds from recovery on insurance claim		1,082
Accrued expenses and other liabilities	(4,347)	1,901
Net cash (used in) provided by operating activities	(13,933)	58,241
Cash flows from investing activities
Purchases of property, plant and equipment	(29,685)	(15,548)
Purchases of marketable securities	(10,843)	(1,290)
Sales of marketable securities	2,492	48,904
Maturities of marketable securities	42,226	2,557
Acquisitions, net of cash acquired	(15,743)	(442,704)
Issuance of a note receivable	(1,000)
Net cash used in investing activities	(12,553)	(408,081)
Cash flows from financing activities
Proceeds from term loans, net of discount		686,386
Proceeds from issuance of common stock	2,332	1,548
Payments of financing costs		(687)
Principal payments on debt	(828)	(354,940)
Payments of capital leases	(957)	(849)
Common stock dividends paid	(22,127)	(21,658)
Net cash (used in) provided by financing activities	(21,580)	309,800
Effects of exchange rate changes on cash and cash equivalents	3,095	(816)
Net decrease in cash, cash equivalents and restricted cash	(44,971)	(40,856)
Cash, cash equivalents and restricted cash, beginning of period	305,171	197,708
Cash, cash equivalents and restricted cash, end of period	260,200	156,852
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property, plant and equipment included in accounts payable	$ 2,020	$ 1,847