Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Operating Activities
Net income (loss)	$ (10,612)	$ 98,626	$ 100,864
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	277,761	201,503	116,467
Stock-based compensation	16,360	16,473	15,071
Certain interest expense and other financing costs	12,102	17,338	10,497
Beneficial lease amortization	2,290	0	0
Loss on debt extinguishment	0	1,248	0
Gain on sale of fixed assets	(3,830)	(1,294)	(839)
Deferred income taxes	(2,555)	(30,118)	393
Changes in operating assets and liabilities, net of the effects of businesses acquired in the period:
Accounts receivable	(18,501)	(45,093)	(60,185)
Inventories	(82,774)	(65,069)	(51,768)
Prepaid expenses and other assets	(70,815)	57,554	(44,208)
Accounts payable and accrued expenses	92,133	287,428	228,908
Other liabilities	1,094	785	0
Net cash provided by (used in) operating activities	212,653	539,381	315,200
Investing Activities
Purchases of property and equipment	(57,031)	(46,010)	(39,828)
Acquisition of businesses, net	(163,973)	(2,740,480)	(129,390)
Proceeds from the sale of assets	9,269	2,149	2,233
Net cash provided by (used in) investing activities	(211,735)	(2,784,341)	(166,985)
Financing Activities
Borrowings under revolving lines of credit	2,100,085	2,807,741	2,464,128
Repayments under revolving lines of credit	(2,113,982)	(2,707,741)	(2,833,230)
Borrowings under term loan	0	970,000	0
Repayments under term loan	(9,700)	(445,850)	(4,500)
Borrowings under senior notes	0	1,300,000	0
Payment of debt issuance costs	(817)	(65,788)	(1,669)
Repayments under equipment financing facilities and other	(10,001)	(11,593)	(10,034)
Proceeds from issuance of convertible preferred stock	0	400,000	0
Proceeds from secondary offering of common stock	0	0	345,503
Payment of stock issuance costs	0	(1,279)	(14,684)
Payment of dividends on preferred stock	(24,000)	(12,978)	0
Proceeds from issuance of common stock related to equity awards	3,314	7,514	11,341
Taxes paid related to net share settlement of equity awards	(3,668)	(3,975)	(392)
Excess tax benefit from stock-based compensation	0	0	2,937
Net cash provided by (used in) financing activities	(58,769)	2,236,051	(40,600)
Effect of exchange rate changes on cash and cash equivalents	211	586	(751)
Net increase (decrease) in cash and cash equivalents	(57,640)	(8,323)	106,864
Cash and cash equivalents, beginning of period	129,927	138,250	31,386
Cash and cash equivalents, end of period	72,287	129,927	138,250
Cash paid during the period for:
Interest	146,425	111,283	49,067
Income taxes paid (received), net of refunds	$ (8,525)	$ 35,105	$ 56,158