Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Statement of Financial Position [Abstract]
Cash and cash equivalents	$ 18,524	$ 53,577
Accounts receivable	243,853	213,016
Accounts and Other Receivables, Net, Current	39,159	40,878
Inventories	71,562	24,889
Costs and estimated earnings in excess of billings	31,962	29,937
Prepaid expenses and other current assets	20,166	9,153
Total current assets	425,226	371,450
Property and equipment, net	35,932	24,589
Goodwill	92,027	53,763
Intangible assets, net	89,301	39,357
Deferred tax assets	23,992	33,803
Operating right of use assets	42,677	31,786
Other non-current assets	6,775	5,780
Total assets	715,930	560,528
Accounts payable and accrued expenses	222,271	186,710
Billings in excess of costs and estimated earnings	67,235	55,739
Total current liabilities	289,506	242,449
Long-term debt	30,576	217
Operating long-term lease liabilities	28,750	20,530
Other non-current liabilities	15,542	12,215
Total liabilities	364,374	275,411
Noncontrolling interest	23,367	1,804
Preferred stock, value	0	0
Common stock, value	220	220
Treasury stock, value	(23,783)	(24,499)
Additional paid-in capital	201,126	200,587
Retained earnings	150,626	107,005
Total stockholders' equity	328,189	283,313
Total liabilities and stockholders' equity	$ 715,930	$ 560,528