CONSOLIDATING GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 10,612	$ 8,753
Net cash provided by (used in) operating activities:	(18,169)	1,041
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of property, plant and equipment	(13,172)	(8,397)
Acquired businesses, net of cash acquired	(10,531)	(9,219)
Proceeds from sale of assets	184	51
Net cash used in investing activities	(23,519)	(17,565)
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase of shares for treasury	(1,758)	(1,348)
Proceeds from long-term debt	71,957	38,965
Payments of long-term debt	(32,045)	(4,322)
Change in short-term borrowings	0	38
Contingent consideration for acquired businesses	0	(1,686)
Financing costs	(21)	(67)
Dividends paid	(3,392)	(3,143)
Other, net	(40)	137
Net cash provided by financing activities	34,701	28,574
CASH FLOWS FROM DISCONTINUED OPERATIONS:
Net cash provided by (used) in discontinued operations	(606)	(458)
Effect of exchange rate changes on cash and equivalents	8	402
NET INCREASE (DECREASE) IN CASH AND EQUIVALENTS	(7,585)	11,994
CASH AND EQUIVALENTS AT BEGINNING OF PERIOD	72,377	69,758
CASH AND EQUIVALENTS AT END OF PERIOD	64,792	81,752
Reportable Legal Entities | Parent Company
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	10,612	8,753
Net cash provided by (used in) operating activities:	(42,309)	(23,532)
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of property, plant and equipment	(212)	(18)
Acquired businesses, net of cash acquired	0	(9,219)
Proceeds from sale of assets	0	0
Net cash used in investing activities	(212)	(9,237)
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase of shares for treasury	(1,758)	(1,348)
Proceeds from long-term debt	65,329	32,412
Payments of long-term debt	(16,179)	(569)
Change in short-term borrowings		0
Contingent consideration for acquired businesses		0
Financing costs	(21)	(67)
Dividends paid	(3,392)	(3,143)
Other, net	(37)	137
Net cash provided by financing activities	43,942	27,422
CASH FLOWS FROM DISCONTINUED OPERATIONS:
Net cash provided by (used) in discontinued operations	0	0
Effect of exchange rate changes on cash and equivalents	0	0
NET INCREASE (DECREASE) IN CASH AND EQUIVALENTS	1,421	(5,347)
CASH AND EQUIVALENTS AT BEGINNING OF PERIOD	1,649	15,976
CASH AND EQUIVALENTS AT END OF PERIOD	3,070	10,629
Reportable Legal Entities | Guarantor Companies
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	18,776	16,804
Net cash provided by (used in) operating activities:	12,888	16,272
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of property, plant and equipment	(12,463)	(6,935)
Acquired businesses, net of cash acquired	0	0
Proceeds from sale of assets	184	38
Net cash used in investing activities	(12,279)	(6,897)
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase of shares for treasury	0	0
Proceeds from long-term debt	13	0
Payments of long-term debt	(40)	(855)
Change in short-term borrowings		38
Contingent consideration for acquired businesses		0
Financing costs	0	0
Dividends paid	0	0
Other, net	(3)	7,240
Net cash provided by financing activities	(30)	6,423
CASH FLOWS FROM DISCONTINUED OPERATIONS:
Net cash provided by (used) in discontinued operations	0	0
Effect of exchange rate changes on cash and equivalents	(264)	(55)
NET INCREASE (DECREASE) IN CASH AND EQUIVALENTS	315	15,743
CASH AND EQUIVALENTS AT BEGINNING OF PERIOD	25,217	16,353
CASH AND EQUIVALENTS AT END OF PERIOD	25,532	32,096
Reportable Legal Entities | Non-Guarantor Companies
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	18,656	16,847
Net cash provided by (used in) operating activities:	11,252	8,301
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of property, plant and equipment	(497)	(1,444)
Acquired businesses, net of cash acquired	(10,531)	0
Proceeds from sale of assets	0	13
Net cash used in investing activities	(11,028)	(1,431)
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase of shares for treasury	0	0
Proceeds from long-term debt	6,615	6,553
Payments of long-term debt	(15,826)	(2,898)
Change in short-term borrowings		0
Contingent consideration for acquired businesses		(1,686)
Financing costs	0	0
Dividends paid	0	0
Other, net	0	(7,240)
Net cash provided by financing activities	(9,211)	(5,271)
CASH FLOWS FROM DISCONTINUED OPERATIONS:
Net cash provided by (used) in discontinued operations	(606)	(458)
Effect of exchange rate changes on cash and equivalents	272	457
NET INCREASE (DECREASE) IN CASH AND EQUIVALENTS	(9,321)	1,598
CASH AND EQUIVALENTS AT BEGINNING OF PERIOD	45,511	37,429
CASH AND EQUIVALENTS AT END OF PERIOD	36,190	39,027
Elimination
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	(37,432)	(33,651)
Net cash provided by (used in) operating activities:	0	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of property, plant and equipment	0	0
Acquired businesses, net of cash acquired	0	0
Proceeds from sale of assets	0	0
Net cash used in investing activities	0	0
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase of shares for treasury	0	0
Proceeds from long-term debt	0	0
Payments of long-term debt	0	0
Change in short-term borrowings		0
Contingent consideration for acquired businesses		0
Financing costs	0	0
Dividends paid	0	0
Other, net	0	0
Net cash provided by financing activities	0	0
CASH FLOWS FROM DISCONTINUED OPERATIONS:
Net cash provided by (used) in discontinued operations	0	0
Effect of exchange rate changes on cash and equivalents	0	0
NET INCREASE (DECREASE) IN CASH AND EQUIVALENTS	0	0
CASH AND EQUIVALENTS AT BEGINNING OF PERIOD	0	0
CASH AND EQUIVALENTS AT END OF PERIOD	$ 0	$ 0