CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net income	$ 13,057	$ 14,415
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	16,477	11,838
Stock-based compensation	4,410	4,467
Amortization of premium on marketable securities and deferred financing costs	67	235
Earnings of equity method investments		(1,772)
Deferred income taxes	(8,183)	(7,682)
Other losses on disposals of assets	126	6
Loss on sale of divestiture, net of tax	319
Changes in operating assets and liabilities, net of acquisitions and divestiture:
Accounts receivable	1,503	(13,826)
Inventories	(4,335)	(12,260)
Prepaid expenses and other assets	6,120	1,029
Accounts payable	5,255	7,932
Deferred revenue	(720)	6,385
Accrued warranty and retrofit costs	221	572
Accrued compensation and tax withholdings	(5,755)	(13,842)
Accrued restructuring costs	(203)	(181)
Accrued expenses and other liabilities	(2,616)	8,948
Net cash provided by operating activities	25,743	6,264
Cash flows from investing activities
Purchases of property, plant and equipment	(9,614)	(3,560)
Purchases of marketable securities	(10,742)	(1,290)
Sales of marketable securities		48,904
Maturities of marketable securities	33,584	2,557
Acquisitions, net of cash acquired		(445,210)
Net cash provided by (used in) investing activities	13,228	(398,599)
Cash flows from financing activities
Proceeds from term loans, net of discount		340,540
Principal payments on debt	(414)	(1,789)
Payments of capital leases	(319)	(121)
Common stock dividends paid	(7,369)	(7,208)
Net cash provided by (used in) financing activities	(8,102)	331,422
Effects of exchange rate changes on cash and cash equivalents	2,808	(1,004)
Net increase (decrease) in cash, cash equivalents and restricted cash	33,677	(61,917)
Cash, cash equivalents and restricted cash, beginning of period	305,171	197,708
Cash, cash equivalents and restricted cash, end of period	338,848	135,791
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property, plant and equipment included in accounts payable	$ 2,622	1,717
Deferred financing costs included in accounts payable		$ 1,750