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		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Condensed Income Statements, Captions [Line Items]
Revenue	$ 495,764	$ 500,107	$ 962,864	$ 994,256
Cost of goods and services	380,215	385,950	731,187	763,994
Gross profit	115,549	114,157	231,677	230,262
Selling, general and administrative expenses	92,489	91,586	182,232	182,885
Income from operations	23,060	22,571	49,445	47,377
Other income (expense)
Interest income (expense), net	(12,622)	(12,348)	(25,989)	(24,360)
Other, net	(199)	(385)	(241)	170
Total other expense, net	(12,821)	(12,733)	(26,230)	(24,190)
Income before taxes	10,239	9,838	23,215	23,187
Provision (benefit) for income taxes	5,194	3,743	5,906	6,304
Income (loss) before equity in net income of subsidiaries	5,045	6,095	17,309	16,883
Equity in net income (loss) of subsidiaries	0	0	0	0
Net income	5,045	6,095	17,309	16,883
Foreign currency translation adjustments	8,409	13,683	(5,070)	10,334
Other comprehensive income (loss), net of taxes	7,933	12,420	(3,379)	8,442
Comprehensive income (loss), net	12,978	18,515	13,930	25,325
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	7,077	6,530	13,721	12,928
Income from operations	(7,077)	(6,530)	(13,721)	(12,928)
Other income (expense)
Interest income (expense), net	(3,322)	(2,696)	(7,349)	(4,952)
Other, net	68	18	161	211
Total other expense, net	(3,254)	(2,678)	(7,188)	(4,741)
Income before taxes	(10,331)	(9,208)	(20,909)	(17,669)
Provision (benefit) for income taxes	(1,534)	(3,650)	(10,563)	(11,639)
Income (loss) before equity in net income of subsidiaries	(8,797)	(5,558)	(10,346)	(6,030)
Equity in net income (loss) of subsidiaries	13,842	11,653	27,655	22,913
Net income	5,045	6,095	17,309	16,883
Other comprehensive income (loss), net of taxes	7,933	12,420	(3,379)	8,442
Comprehensive income (loss), net	12,978	18,515	13,930	25,325
Guarantor Companies [Member]
Condensed Income Statements, Captions [Line Items]
Revenue	396,637	406,989	756,498	796,249
Cost of goods and services	304,706	313,203	576,438	611,587
Gross profit	91,931	93,786	180,060	184,662
Selling, general and administrative expenses	66,234	66,197	129,231	132,144
Income from operations	25,697	27,589	50,829	52,518
Other income (expense)
Interest income (expense), net	(8,233)	(7,752)	(16,291)	(15,541)
Other, net	908	904	1,559	1,920
Total other expense, net	(7,325)	(6,848)	(14,732)	(13,621)
Income before taxes	18,372	20,741	36,097	38,897
Provision (benefit) for income taxes	5,428	8,012	13,096	16,829
Income (loss) before equity in net income of subsidiaries	12,944	12,729	23,001	22,068
Equity in net income (loss) of subsidiaries	922	(1,108)	4,720	821
Net income	13,866	11,621	27,721	22,889
Other comprehensive income (loss), net of taxes	(3,590)	2,062	(7,907)	2,201
Comprehensive income (loss), net	10,276	13,683	19,814	25,090
Non-Guarantor Companies [Member]
Condensed Income Statements, Captions [Line Items]
Revenue	108,571	100,614	223,420	213,346
Cost of goods and services	85,224	80,493	172,324	168,389
Gross profit	23,347	20,121	51,096	44,957
Selling, general and administrative expenses	19,271	18,952	39,465	37,998
Income from operations	4,076	1,169	11,631	6,959
Other income (expense)
Interest income (expense), net	(1,067)	(1,900)	(2,349)	(3,867)
Other, net	(811)	(964)	(1,255)	(1,133)
Total other expense, net	(1,878)	(2,864)	(3,604)	(5,000)
Income before taxes	2,198	(1,695)	8,027	1,959
Provision (benefit) for income taxes	1,300	(619)	3,373	1,114
Income (loss) before equity in net income of subsidiaries	898	(1,076)	4,654	845
Equity in net income (loss) of subsidiaries	12,944	12,730	23,001	22,068
Net income	13,842	11,654	27,655	22,913
Other comprehensive income (loss), net of taxes	(8,280)	10,358	5,354	6,241
Comprehensive income (loss), net	5,562	22,012	33,009	29,154
Elimination [Member]
Condensed Income Statements, Captions [Line Items]
Revenue	(9,444)	(7,496)	(17,054)	(15,339)
Cost of goods and services	(9,715)	(7,746)	(17,575)	(15,982)
Gross profit	271	250	521	643
Selling, general and administrative expenses	(93)	(93)	(185)	(185)
Income from operations	364	343	706	828
Other income (expense)
Interest income (expense), net	0	0	0	0
Other, net	(364)	(343)	(706)	(828)
Total other expense, net	(364)	(343)	(706)	(828)
Income before taxes	0	0	0	0
Provision (benefit) for income taxes	0	0	0	0
Income (loss) before equity in net income of subsidiaries	0	0	0	0
Equity in net income (loss) of subsidiaries	(27,708)	(23,275)	(55,376)	(45,802)
Net income	(27,708)	(23,275)	(55,376)	(45,802)
Other comprehensive income (loss), net of taxes	11,870	(12,420)	2,553	(8,442)
Comprehensive income (loss), net	$ (15,838)	$ (35,695)	$ (52,823)	$ (54,244)