CONSOLIDATING GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details) - Summary of consolidated statement of operations and comprehensive income - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Condensed Income Statements, Captions [Line Items]
Revenue	$ 574,164	$ 574,970	$ 549,633	$ 510,522	$ 545,505	$ 516,550	$ 478,560	$ 437,303	$ 2,209,289	$ 1,977,918	$ 1,524,997
Cost of goods and services									1,614,020	1,448,737	1,116,871
Gross profit	160,236	154,483	137,504	143,046	148,341	138,682	121,379	120,779	595,269	529,181	408,126
Selling, general and administrative expenses									460,004	436,380	341,092
Income from continuing operations									135,265	92,801	67,034
Other income (expense)
Interest income (expense), net									(67,260)	(63,871)	(51,449)
Other, net									4,173	4,880	1,113
Total other income (expense)									(63,087)	(58,991)	(50,336)
Income before taxes from continuing operations									72,178	33,810	16,698
Provision (benefit) for income taxes									26,556	555	(1,085)
Income (loss) before equity in net income of subsidiaries									45,622	33,255	17,783
Equity in net income (loss) of subsidiaries									0	0	0
Income (loss) from continuing operations	$ 16,251	$ 14,128	$ 6,490	$ 8,753	$ 1,031	$ 7,442	$ 1,951	$ 22,831	45,622	33,255	17,783
Income (loss) from operations of discontinued businesses									(11,050)	119,981	22,276
Provision for income taxes									(2,715)	27,558	25,147
Income (loss) from discontinued operations									(8,335)	92,423	(2,871)
Net income									37,287	125,678	14,912
Comprehensive income (loss)									5,483	152,047	35,672
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									0	0	0
Cost of goods and services									0	0	0
Gross profit									0	0	0
Selling, general and administrative expenses									22,566	37,540	40,231
Income from continuing operations									(22,566)	(37,540)	(40,231)
Other income (expense)
Interest income (expense), net									(27,883)	(23,911)	(13,804)
Other, net									(778)	(7,666)	(1,983)
Total other income (expense)									(28,661)	(31,577)	(15,787)
Income before taxes from continuing operations									(51,227)	(69,117)	(56,018)
Provision (benefit) for income taxes									(7,425)	(17,692)	(11,338)
Income (loss) before equity in net income of subsidiaries									(43,802)	(51,425)	(44,680)
Equity in net income (loss) of subsidiaries									81,089	177,103	59,592
Income (loss) from continuing operations									37,287	125,678	14,912
Income (loss) from operations of discontinued businesses									0	0	0
Provision for income taxes									0	0	0
Income (loss) from discontinued operations									0	0	0
Net income									37,287	125,678	14,912
Comprehensive income (loss)									5,483	152,047	35,672
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									1,808,824	1,638,792	1,284,189
Cost of goods and services									1,341,868	1,232,398	966,283
Gross profit									466,956	406,394	317,906
Selling, general and administrative expenses									340,147	308,338	236,766
Income from continuing operations									126,809	98,056	81,140
Other income (expense)
Interest income (expense), net									(39,288)	(31,913)	(24,242)
Other, net									(16,653)	125,531	5,431
Total other income (expense)									(55,941)	93,618	(18,811)
Income before taxes from continuing operations									70,868	191,674	62,329
Provision (benefit) for income taxes									20,534	9,546	24,560
Income (loss) before equity in net income of subsidiaries									50,334	182,128	37,769
Equity in net income (loss) of subsidiaries									44,303	(151,864)	(25,231)
Income (loss) from continuing operations									94,637	30,264	12,538
Income (loss) from operations of discontinued businesses									0	119,981	16,827
Provision for income taxes									0	27,558	4,476
Income (loss) from discontinued operations									0	92,423	12,351
Net income									94,637	122,687	24,889
Comprehensive income (loss)									87,851	143,936	35,575
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									437,542	367,149	270,520
Cost of goods and services									310,707	245,687	181,634
Gross profit									126,835	121,462	88,886
Selling, general and administrative expenses									97,661	90,872	64,465
Income from continuing operations									29,174	30,590	24,421
Other income (expense)
Interest income (expense), net									(89)	(8,047)	(13,403)
Other, net									23,452	(111,248)	(631)
Total other income (expense)									23,363	(119,295)	(14,034)
Income before taxes from continuing operations									52,537	(88,705)	10,387
Provision (benefit) for income taxes									13,447	8,743	(14,307)
Income (loss) before equity in net income of subsidiaries									39,090	(97,448)	24,694
Equity in net income (loss) of subsidiaries									50,334	182,128	37,770
Income (loss) from continuing operations									89,424	84,680	62,464
Income (loss) from operations of discontinued businesses									(11,050)	0	5,449
Provision for income taxes									(2,715)	0	20,671
Income (loss) from discontinued operations									(8,335)	0	(15,222)
Net income									81,089	84,680	47,242
Comprehensive income (loss)									87,875	81,389	38,337
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Revenue									(37,077)	(28,023)	(29,712)
Cost of goods and services									(38,555)	(29,348)	(31,046)
Gross profit									1,478	1,325	1,334
Selling, general and administrative expenses									(370)	(370)	(370)
Income from continuing operations									1,848	1,695	1,704
Other income (expense)
Interest income (expense), net									0	0	0
Other, net									(1,848)	(1,737)	(1,704)
Total other income (expense)									(1,848)	(1,737)	(1,704)
Income before taxes from continuing operations									0	(42)	0
Provision (benefit) for income taxes									0	(42)	0
Income (loss) before equity in net income of subsidiaries									0	0	0
Equity in net income (loss) of subsidiaries									(175,726)	(207,367)	(72,131)
Income (loss) from continuing operations									(175,726)	(207,367)	(72,131)
Income (loss) from operations of discontinued businesses									0	0	0
Provision for income taxes									0	0	0
Income (loss) from discontinued operations									0	0	0
Net income									(175,726)	(207,367)	(72,131)
Comprehensive income (loss)									$ (175,726)	$ (225,325)	$ (73,912)