Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Cash Flows [Abstract]
Net income (loss)	$ 14,743	$ 12,440
Bad debt expense	281	248
Deferred financing cost amortization	204	156
Depreciation and amortization	5,597	4,846
Loss (gain) on sale of assets	(37)	95
Non-cash compensation expense	1,684	674
Deferred income taxes	4,543	4,243
Accounts receivable	8,595	(9,616)
Inventories	(220)	(2,873)
Costs and estimated earnings in excess of billings	2,847	3,152
Prepaid expenses and other current assets	(8,942)	(764)
Other non-current assets	1,543	(1,370)
Accounts payable and accrued expenses	(2,035)	(144)
Billings in excess of costs and estimated earnings	4,113	(948)
Other non-current liabilities	(195)	(736)
Net cash provided by operating activities	32,721	9,403
Purchases of property and equipment	(2,898)	(3,929)
Proceeds from sale of assets	53	7
Cash paid in conjunction with business combinations	(28,952)
Net cash used in investing activities	(31,797)	(3,922)
Borrowings of debt	592,422	122
Repayments of debt	(563,093)	(10,144)
Cash paid for finance leases	(71)
Distribution to noncontrolling interests	(457)	(137)
Purchase of treasury stock	(4,894)	(5,411)
Options exercised	34
Net cash used in financing activities	23,941	(15,570)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	24,865	(10,089)
CASH, CASH EQUIVALENTS and RESTRiCTED CASH, beginning of period	18,934	26,247
CASH, CASH EQUIVALENTS and RESTRICTED CASH, end of period	43,799	16,158
Cash paid for interest	410	1,008
Cash paid for income taxes (net)	$ 522	$ 523