CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net income	$ 17,836	$ 83,506
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	26,339	17,634
Stock-based compensation	9,717	10,129
Amortization of premium on marketable securities and deferred financing costs	556	217
Earnings of equity method investments	(3,041)	(3,602)
Loss recovery on insurance claim		(1,103)
Deferred income tax benefit	(12,472)	(49,156)
Loss on extinguishment of debt	9,051
Other gains on disposals of assets	34
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(9,654)	(16,949)
Inventories	(9,992)	(16,233)
Prepaid expenses and other assets	1,938	(17,248)
Accounts payable	(6,088)	14,899
Deferred revenue	5,410	(2,783)
Accrued warranty and retrofit costs	740	(16)
Accrued compensation and tax withholdings	(11,123)	(4,151)
Accrued restructuring costs	(57)	(1,336)
Proceeds from recovery on insurance claim	886
Accrued expenses and other liabilities	2,149	9,619
Net cash provided by operating activities	22,229	23,427
Cash flows from investing activities
Purchases of property, plant and equipment	(9,676)	(5,675)
Purchases of marketable securities	(1,290)	(49,560)
Sales of marketable securities	48,904
Maturities of marketable securities	2,557	100
Acquisitions, net of cash acquired	(442,704)	(64,988)
Proceeds from sales of property, plant and equipment		200
Net cash used in investing activities	(402,209)	(119,923)
Cash flows from financing activities
Proceeds from term loans, net of discount	686,386	197,554
Proceeds from issuance of common stock	1,548	1,395
Payment of financing costs	(687)	(318)
Principal payments on debt	(352,289)	(500)
Payment of capital lease	(487)
Common stock dividends paid	(14,429)	(14,125)
Net cash provided by financing activities	320,042	184,006
Effects of exchange rate changes on cash and cash equivalents	(553)	4,884
Net increase (decrease) in cash and cash equivalents	(60,491)	92,394
Cash and cash equivalents, beginning of period	197,708	101,622
Cash and cash equivalents, end of period	137,217	194,016
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property, plant and equipment included in accounts payable	$ 1,670	$ 716