CONSOLIDATING GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details) - Summary of Condensed Consolidating Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018
Condensed Income Statements, Captions [Line Items]
Revenue	$ 574,970			$ 516,550			$ 1,635,125	$ 1,432,413
Cost of goods and services	420,487			377,868			1,200,092	1,051,573
Gross profit	154,483			138,682			435,033	380,840
Selling, general and administrative expenses	117,989			115,112			343,526	326,229
Income from operations	36,494			23,570			91,507	54,611
Other income (expense)
Interest income (expense), net	(17,087)			(15,796)			(50,723)	(48,482)
Other, net	979			1,228			3,251	3,988
Total other expense, net	(16,108)			(14,568)			(47,472)	(44,494)
Income before taxes from continuing operations	20,386			9,002			44,035	10,117
Provision (benefit) for income taxes	6,258			1,560			14,664	(22,107)
Income (loss) before equity in net income of subsidiaries	14,128			7,442			29,371	32,224
Equity in net income (loss) of subsidiaries	0			0			0	0
Income from continuing operations	14,128			7,442			29,371	32,224
Income (loss) from operations of discontinued operations	0			(200)			(11,000)	124,642
Provision (benefit) for income taxes	533			1,415			(2,821)	29,770
Income (loss) from discontinued operations	(533)			(1,615)			(8,179)	94,872
Net income	13,595	$ (1,156)	$ 8,753	5,827	$ 90,280	$ 30,989	21,192	127,096
Comprehensive income (loss), net	12,560			(2,978)			17,587	147,050
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Revenue	0			0			0	0
Cost of goods and services	0			0			0	0
Gross profit	0			0			0	0
Selling, general and administrative expenses	5,342			14,383			15,651	31,158
Income from operations	(5,342)			(14,383)			(15,651)	(31,158)
Other income (expense)
Interest income (expense), net	(7,171)			(5,891)			(20,806)	(18,626)
Other, net	4,963			(528)			4,228	164
Total other expense, net	(2,208)			(6,419)			(16,578)	(18,462)
Income before taxes from continuing operations	(7,550)			(20,802)			(32,229)	(49,620)
Provision (benefit) for income taxes	(4,815)			(4,741)			(12,592)	(44,601)
Income (loss) before equity in net income of subsidiaries	(2,735)			(16,061)			(19,637)	(5,019)
Equity in net income (loss) of subsidiaries	16,330			21,888			40,829	132,115
Income from continuing operations	13,595			5,827			21,192	127,096
Income (loss) from operations of discontinued operations	0			0			0	0
Provision (benefit) for income taxes	0			0			0	0
Income (loss) from discontinued operations	0			0			0	0
Net income	13,595			5,827			21,192	127,096
Comprehensive income (loss), net	12,560			(2,978)			17,587	147,050
Guarantor Companies [Member]
Condensed Income Statements, Captions [Line Items]
Revenue	470,228			431,997			1,352,211	1,181,068
Cost of goods and services	350,197			323,091			1,013,676	891,650
Gross profit	120,031			108,906			338,535	289,418
Selling, general and administrative expenses	85,885			78,865			255,674	220,066
Income from operations	34,146			30,041			82,861	69,352
Other income (expense)
Interest income (expense), net	(9,048)			(2,282)			(27,306)	(16,497)
Other, net	(15,918)			(8,496)			(14,102)	4,858
Total other expense, net	(24,966)			(10,778)			(41,408)	(11,639)
Income before taxes from continuing operations	9,180			19,263			41,453	57,713
Provision (benefit) for income taxes	9,124			21,046			20,390	13,744
Income (loss) before equity in net income of subsidiaries	56			(1,783)			21,063	43,969
Equity in net income (loss) of subsidiaries	15,641			(5,657)			33,337	(66,016)
Income from continuing operations	15,697			(7,440)			54,400	(22,047)
Income (loss) from operations of discontinued operations	0			(200)			0	109,028
Provision (benefit) for income taxes	0			1,415			0	31,856
Income (loss) from discontinued operations	0			(1,615)			0	77,172
Net income	15,697			(9,055)			54,400	55,125
Comprehensive income (loss), net	(597)			433			58,450	36,517
Non-Guarantor Companies [Member]
Condensed Income Statements, Captions [Line Items]
Revenue	118,694			90,285			311,219	272,714
Cost of goods and services	84,568			60,719			215,786	182,125
Gross profit	34,126			29,566			95,433	90,589
Selling, general and administrative expenses	27,252			21,956			72,478	75,282
Income from operations	6,874			7,610			22,955	15,307
Other income (expense)
Interest income (expense), net	(868)			(7,623)			(2,611)	(13,359)
Other, net	12,762			10,481			14,479	119
Total other expense, net	11,894			2,858			11,868	(13,240)
Income before taxes from continuing operations	18,768			10,468			34,823	2,067
Provision (benefit) for income taxes	1,961			12,939			6,878	8,793
Income (loss) before equity in net income of subsidiaries	16,807			(2,471)			27,945	(6,726)
Equity in net income (loss) of subsidiaries	56			(2,016)			21,063	43,735
Income from continuing operations	16,863			(4,487)			49,008	37,009
Income (loss) from operations of discontinued operations	0			0			(11,000)	15,614
Provision (benefit) for income taxes	533			0			(2,821)	(2,086)
Income (loss) from discontinued operations	(533)			0			(8,179)	17,700
Net income	16,330			(4,487)			40,829	54,709
Comprehensive income (loss), net	32,624			(14,092)			36,779	73,317
Elimination [Member]
Condensed Income Statements, Captions [Line Items]
Revenue	(13,952)			(5,732)			(28,305)	(21,369)
Cost of goods and services	(14,278)			(5,942)			(29,370)	(22,202)
Gross profit	326			210			1,065	833
Selling, general and administrative expenses	(490)			(92)			(277)	(277)
Income from operations	816			302			1,342	1,110
Other income (expense)
Interest income (expense), net	0			0			0	0
Other, net	(828)			(229)			(1,354)	(1,153)
Total other expense, net	(828)			(229)			(1,354)	(1,153)
Income before taxes from continuing operations	(12)			73			(12)	(43)
Provision (benefit) for income taxes	(12)			(27,684)			(12)	(43)
Income (loss) before equity in net income of subsidiaries	0			27,757			0	0
Equity in net income (loss) of subsidiaries	(32,027)			(14,215)			(95,229)	(109,834)
Income from continuing operations	(32,027)			13,542			(95,229)	(109,834)
Income (loss) from operations of discontinued operations	0			0			0	0
Provision (benefit) for income taxes	0			0			0	0
Income (loss) from discontinued operations	0			0			0	0
Net income	(32,027)			13,542			(95,229)	(109,834)
Comprehensive income (loss), net	$ (32,027)			$ 13,659			$ (95,229)	$ (109,834)