CONSOLIDATING GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details) - Summary of consolidated balance sheets - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
CURRENT ASSETS
Cash and equivalents	$ 69,758	$ 47,681	$ 72,553	$ 52,001
Accounts receivable, net of allowances	280,509	208,229
Contract costs and recognized income not yet billed, net of progress payments	121,803	131,662
Inventories	398,359	299,437
Prepaid and other current assets	42,121	40,067
Assets of discontinued operations held for sale	0	370,724
Assets of discontinued operations not held for sale	324	329
Total Current Assets	912,874	1,098,129
PROPERTY, PLANT AND EQUIPMENT, net	342,492	232,135
GOODWILL	439,395	319,139	306,163
INTANGIBLE ASSETS, net	370,858	205,127
INTERCOMPANY RECEIVABLE	0	0
EQUITY INVESTMENTS IN SUBSIDIARIES	0	0
OTHER ASSETS	16,355	16,051
ASSETS OF DISCONTINUED OPERATIONS	2,916	2,960
Total Assets	2,084,890	1,873,541	1,782,096
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	13,011	11,078
Accounts payable and accrued liabilities	372,850	267,209
Liabilities of discontinued operations held for sale	0	84,450
Liabilities of discontinued operations	7,210	8,342
Total Current Liabilities	393,071	371,079
LONG-TERM DEBT, net of debt discounts	1,108,071	968,080
INTERCOMPANY PAYABLES	0	0
OTHER LIABILITIES	106,710	132,537
LIABILITIES OF DISCONTINUED OPERATIONS	2,647	3,037
Total Liabilities	1,610,499	1,474,733
SHAREHOLDERS’ EQUITY	474,391	398,808	410,947	430,525
Total Liabilities and Shareholders’ Equity	2,084,890	1,873,541
Parent Company [Member]
CURRENT ASSETS
Cash and equivalents	15,976	3,240	6,517	2,440
Accounts receivable, net of allowances	0	0
Contract costs and recognized income not yet billed, net of progress payments	0	0
Inventories	0	0
Prepaid and other current assets	12,179	21,131
Assets of discontinued operations held for sale		0
Assets of discontinued operations not held for sale	0	0
Total Current Assets	28,155	24,371
PROPERTY, PLANT AND EQUIPMENT, net	936	645
GOODWILL	6,646	0
INTANGIBLE ASSETS, net	93	93
INTERCOMPANY RECEIVABLE	56,396	552,017
EQUITY INVESTMENTS IN SUBSIDIARIES	1,528,932	863,149
OTHER ASSETS	8,651	12,171
ASSETS OF DISCONTINUED OPERATIONS	0	0
Total Assets	1,629,809	1,452,446
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	2,276	2,854
Accounts payable and accrued liabilities	26,639	14,683
Liabilities of discontinued operations held for sale		0
Liabilities of discontinued operations	0	0
Total Current Liabilities	28,915	17,537
LONG-TERM DEBT, net of debt discounts	1,044,071	903,609
INTERCOMPANY PAYABLES	66,058	84,068
OTHER LIABILITIES	16,374	48,424
LIABILITIES OF DISCONTINUED OPERATIONS	0	0
Total Liabilities	1,155,418	1,053,638
SHAREHOLDERS’ EQUITY	474,391	398,808
Total Liabilities and Shareholders’ Equity	1,629,809	1,452,446
Guarantor Subsidiaries [Member]
CURRENT ASSETS
Cash and equivalents	16,353	8,066	27,692	10,672
Accounts receivable, net of allowances	234,885	168,731
Contract costs and recognized income not yet billed, net of progress payments	121,393	131,383
Inventories	332,067	246,605
Prepaid and other current assets	21,313	15,854
Assets of discontinued operations held for sale		168,306
Assets of discontinued operations not held for sale	0	0
Total Current Assets	726,011	738,945
PROPERTY, PLANT AND EQUIPMENT, net	299,920	200,362
GOODWILL	361,507	280,797
INTANGIBLE ASSETS, net	293,093	143,415
INTERCOMPANY RECEIVABLE	314,394	757,608
EQUITY INVESTMENTS IN SUBSIDIARIES	968,330	877,641
OTHER ASSETS	15,942	12,054
ASSETS OF DISCONTINUED OPERATIONS	0	0
Total Assets	2,979,197	3,010,822
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	3,398	1,471
Accounts payable and accrued liabilities	303,154	199,784
Liabilities of discontinued operations held for sale		47,426
Liabilities of discontinued operations	(22,327)	0
Total Current Liabilities	284,225	248,681
LONG-TERM DEBT, net of debt discounts	6,110	6,044
INTERCOMPANY PAYABLES	(77,760)	1,259,413
OTHER LIABILITIES	73,391	76,036
LIABILITIES OF DISCONTINUED OPERATIONS	0	0
Total Liabilities	285,966	1,590,174
SHAREHOLDERS’ EQUITY	2,693,231	1,420,648
Total Liabilities and Shareholders’ Equity	2,979,197	3,010,822
Non-Guarantor Subsidiaries [Member]
CURRENT ASSETS
Cash and equivalents	37,429	36,375	38,344	38,889
Accounts receivable, net of allowances	69,729	59,929
Contract costs and recognized income not yet billed, net of progress payments	410	279
Inventories	66,373	52,759
Prepaid and other current assets	6,168	3,002
Assets of discontinued operations held for sale		202,418
Assets of discontinued operations not held for sale	324	329
Total Current Assets	180,433	355,091
PROPERTY, PLANT AND EQUIPMENT, net	41,636	31,128
GOODWILL	71,242	38,342
INTANGIBLE ASSETS, net	77,672	61,619
INTERCOMPANY RECEIVABLE	(121,445)	915,551
EQUITY INVESTMENTS IN SUBSIDIARIES	3,347,894	1,613,891
OTHER ASSETS	374	(1,002)
ASSETS OF DISCONTINUED OPERATIONS	2,916	2,960
Total Assets	3,600,722	3,017,580
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	7,337	6,753
Accounts payable and accrued liabilities	59,531	46,111
Liabilities of discontinued operations held for sale		37,024
Liabilities of discontinued operations	29,537	8,342
Total Current Liabilities	96,405	98,230
LONG-TERM DEBT, net of debt discounts	57,890	58,427
INTERCOMPANY PAYABLES	263,227	854,518
OTHER LIABILITIES	20,592	14,135
LIABILITIES OF DISCONTINUED OPERATIONS	2,647	3,037
Total Liabilities	440,761	1,028,347
SHAREHOLDERS’ EQUITY	3,159,961	1,989,233
Total Liabilities and Shareholders’ Equity	3,600,722	3,017,580
Consolidation, Eliminations [Member]
CURRENT ASSETS
Cash and equivalents	0	0	$ 0	$ 0
Accounts receivable, net of allowances	(24,105)	(20,431)
Contract costs and recognized income not yet billed, net of progress payments	0	0
Inventories	(81)	73
Prepaid and other current assets	2,461	80
Assets of discontinued operations held for sale		0
Assets of discontinued operations not held for sale	0	0
Total Current Assets	(21,725)	(20,278)
PROPERTY, PLANT AND EQUIPMENT, net	0	0
GOODWILL	0	0
INTANGIBLE ASSETS, net	0	0
INTERCOMPANY RECEIVABLE	(249,345)	(2,225,176)
EQUITY INVESTMENTS IN SUBSIDIARIES	(5,845,156)	(3,354,681)
OTHER ASSETS	(8,612)	(7,172)
ASSETS OF DISCONTINUED OPERATIONS	0	0
Total Assets	(6,124,838)	(5,607,307)
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	0	0
Accounts payable and accrued liabilities	(16,474)	6,631
Liabilities of discontinued operations held for sale		0
Liabilities of discontinued operations	0	0
Total Current Liabilities	(16,474)	6,631
LONG-TERM DEBT, net of debt discounts	0	0
INTERCOMPANY PAYABLES	(251,525)	(2,197,999)
OTHER LIABILITIES	(3,647)	(6,058)
LIABILITIES OF DISCONTINUED OPERATIONS	0	0
Total Liabilities	(271,646)	(2,197,426)
SHAREHOLDERS’ EQUITY	(5,853,192)	(3,409,881)
Total Liabilities and Shareholders’ Equity	$ (6,124,838)	$ (5,607,307)