CONSOLIDATING GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details) - Summary of Condensed Consolidating Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
CURRENT ASSETS
Cash and equivalents	$ 84,420	$ 47,681	$ 52,269	$ 72,553
Accounts receivable, net of allowances	212,023	208,229
Contract costs and recognized income not yet billed, net of progress payments	120,200	131,662
Inventories, net	359,844	299,437
Prepaid and other current assets	64,837	40,067
Assets of discontinued operations	377,275	370,724
Assets of discontinued operations not held for sale	328	329
Total Current Assets	1,218,927	1,098,129
PROPERTY, PLANT AND EQUIPMENT, net	280,725	232,135
GOODWILL	385,076	319,139
INTANGIBLE ASSETS, net	277,160	205,127
INTERCOMPANY RECEIVABLE	0	0
EQUITY INVESTMENTS IN SUBSIDIARIES	0	0
OTHER ASSETS	15,675	16,051
ASSETS OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	2,952	2,960
Total Assets	2,180,515	1,873,541
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	12,593	11,078
Accounts payable and accrued liabilities	315,296	267,209
Liabilities of discontinued operations	85,737	84,450
Liabilities of discontinued operations not held for sale	3,924	8,342
Total Current Liabilities	417,550	371,079
LONG-TERM DEBT, net of debt discounts	1,238,393	968,080
INTERCOMPANY PAYABLES	0	0
OTHER LIABILITIES	84,534	132,537
LIABILITIES OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	5,225	3,037
Total Liabilities	1,745,702	1,474,733
Total Shareholders’ Equity	434,813	398,808
Total Liabilities and Shareholders’ Equity	2,180,515	1,873,541
Parent Company [Member]
CURRENT ASSETS
Cash and equivalents	5,931	3,240	1,726	6,517
Accounts receivable, net of allowances	0	0
Contract costs and recognized income not yet billed, net of progress payments	0	0
Inventories, net	0	0
Prepaid and other current assets	34,622	21,131
Assets of discontinued operations	0
Assets of discontinued operations not held for sale	0	0
Total Current Assets	40,553	24,371
PROPERTY, PLANT AND EQUIPMENT, net	715	645
GOODWILL	0	0
INTANGIBLE ASSETS, net	93	93
INTERCOMPANY RECEIVABLE	587,623	552,017
EQUITY INVESTMENTS IN SUBSIDIARIES	1,066,860	863,149
OTHER ASSETS	6,070	12,171
ASSETS OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	0	0
Total Assets	1,701,914	1,452,446
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	2,854	2,854
Accounts payable and accrued liabilities	37,122	14,683
Liabilities of discontinued operations	0	0
Liabilities of discontinued operations not held for sale	0	0
Total Current Liabilities	39,976	17,537
LONG-TERM DEBT, net of debt discounts	1,177,811	903,609
INTERCOMPANY PAYABLES	63,607	84,068
OTHER LIABILITIES	(14,293)	48,424
LIABILITIES OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	0	0
Total Liabilities	1,267,101	1,053,638
Total Shareholders’ Equity	434,813	398,808
Total Liabilities and Shareholders’ Equity	1,701,914	1,452,446
Guarantor Companies [Member]
CURRENT ASSETS
Cash and equivalents	31,437	8,066	13,749	27,692
Accounts receivable, net of allowances	174,330	168,731
Contract costs and recognized income not yet billed, net of progress payments	119,529	131,383
Inventories, net	307,201	246,605
Prepaid and other current assets	20,748	15,854
Assets of discontinued operations	176,788	168,306
Assets of discontinued operations not held for sale	0	0
Total Current Assets	830,033	738,945
PROPERTY, PLANT AND EQUIPMENT, net	248,481	200,362
GOODWILL	346,898	280,797
INTANGIBLE ASSETS, net	216,478	143,415
INTERCOMPANY RECEIVABLE	772,461	757,608
EQUITY INVESTMENTS IN SUBSIDIARIES	883,171	877,641
OTHER ASSETS	12,402	12,054
ASSETS OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	0	0
Total Assets	3,309,924	3,010,822
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	3,249	1,471
Accounts payable and accrued liabilities	229,702	199,784
Liabilities of discontinued operations	42,635	47,426
Liabilities of discontinued operations not held for sale	0	0
Total Current Liabilities	275,586	248,681
LONG-TERM DEBT, net of debt discounts	8,610	6,044
INTERCOMPANY PAYABLES	1,324,279	1,259,413
OTHER LIABILITIES	76,997	76,036
LIABILITIES OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	0	0
Total Liabilities	1,685,472	1,590,174
Total Shareholders’ Equity	1,624,452	1,420,648
Total Liabilities and Shareholders’ Equity	3,309,924	3,010,822
Non-Guarantor Companies [Member]
CURRENT ASSETS
Cash and equivalents	47,052	36,375	36,794	38,344
Accounts receivable, net of allowances	60,864	59,929
Contract costs and recognized income not yet billed, net of progress payments	671	279
Inventories, net	52,573	52,759
Prepaid and other current assets	3,499	3,002
Assets of discontinued operations	200,487	202,418
Assets of discontinued operations not held for sale	328	329
Total Current Assets	365,474	355,091
PROPERTY, PLANT AND EQUIPMENT, net	31,529	31,128
GOODWILL	38,178	38,342
INTANGIBLE ASSETS, net	60,589	61,619
INTERCOMPANY RECEIVABLE	391,237	915,551
EQUITY INVESTMENTS IN SUBSIDIARIES	1,817,051	1,613,891
OTHER ASSETS	(1,323)	(1,002)
ASSETS OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	2,952	2,960
Total Assets	2,705,687	3,017,580
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	6,490	6,753
Accounts payable and accrued liabilities	56,099	46,111
Liabilities of discontinued operations	43,102	37,024
Liabilities of discontinued operations not held for sale	3,924	8,342
Total Current Liabilities	109,615	98,230
LONG-TERM DEBT, net of debt discounts	51,972	58,427
INTERCOMPANY PAYABLES	334,212	854,518
OTHER LIABILITIES	4,919	14,135
LIABILITIES OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	5,225	3,037
Total Liabilities	505,943	1,028,347
Total Shareholders’ Equity	2,199,744	1,989,233
Total Liabilities and Shareholders’ Equity	2,705,687	3,017,580
Elimination [Member]
CURRENT ASSETS
Cash and equivalents	0	0	$ 0	$ 0
Accounts receivable, net of allowances	(23,171)	(20,431)
Contract costs and recognized income not yet billed, net of progress payments	0	0
Inventories, net	70	73
Prepaid and other current assets	5,968	80
Assets of discontinued operations	0	0
Assets of discontinued operations not held for sale	0	0
Total Current Assets	(17,133)	(20,278)
PROPERTY, PLANT AND EQUIPMENT, net	0	0
GOODWILL	0	0
INTANGIBLE ASSETS, net	0	0
INTERCOMPANY RECEIVABLE	(1,751,321)	(2,225,176)
EQUITY INVESTMENTS IN SUBSIDIARIES	(3,767,082)	(3,354,681)
OTHER ASSETS	(1,474)	(7,172)
ASSETS OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	0	0
Total Assets	(5,537,010)	(5,607,307)
CURRENT LIABILITIES
Notes payable and current portion of long-term debt	0	0
Accounts payable and accrued liabilities	(7,627)	6,631
Liabilities of discontinued operations	0	0
Liabilities of discontinued operations not held for sale	0	0
Total Current Liabilities	(7,627)	6,631
LONG-TERM DEBT, net of debt discounts	0	0
INTERCOMPANY PAYABLES	(1,722,098)	(2,197,999)
OTHER LIABILITIES	16,911	(6,058)
LIABILITIES OF DISCONTINUED OPERATIONS NOT HELD FOR SALE	0	0
Total Liabilities	(1,712,814)	(2,197,426)
Total Shareholders’ Equity	(3,824,196)	(3,409,881)
Total Liabilities and Shareholders’ Equity	$ (5,537,010)	$ (5,607,307)