REVENUES (Amount Of Each Financial Statement to apply New Accounting Standard) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Consolidated Balance Sheets
Contract assets		$ 100,540		$ 100,540		$ 53,034
Inventories		124,493		124,493		135,416
Total current assets		435,959		435,959		396,023
Total assets		1,293,963		1,293,963		1,265,122
Contract liabilities		55,453		55,453		49,035
Total current liabilities		201,945		201,945		200,530
Deferred tax liabilities		62,938		62,938
Total liabilities		499,567		499,567		505,712
Retained earnings		643,018		643,018		606,837
Total shareholders' equity		794,396		794,396		759,410
Total liabilities and shareholders' equity		1,293,963		1,293,963		$ 1,265,122
Consolidated Statements of Operations
Net sales		193,949	$ 174,778	376,546	$ 348,273
Cost of sales		121,946	112,370	240,854	224,106
Total costs and expenses		172,594	161,194	331,934	321,888
Earnings before income tax		21,355	13,584	44,612	26,385
Income tax (benefit) expense		2,558	3,590	8,498	(18,280)
Net earnings		$ 18,797	$ 9,994	$ 36,114	$ 44,665
Basic:
Net earnings		$ 0.73	$ 0.39	$ 1.39	$ 1.73
Diluted:
Net earnings		$ 0.72	$ 0.38	$ 1.38	$ 1.72
Consolidated Statements of Comprehensive Income
Net earnings		$ 18,797	$ 9,994	$ 36,114	$ 44,665
Comprehensive income		19,600	12,969	32,362	48,945
Consolidated Statements of Cash flows
Net earnings		18,797	$ 9,994	36,114	44,665
Adjustments to reconcile net earnings to net cash provided by operating activities:
Change in assets and liabilities				(28,847)	(5,570)
Net cash provided by operating activities				16,992	$ 33,471
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Consolidated Balance Sheets
Contract assets	[1]	(39,565)		(39,565)
Inventories		34,692		34,692
Total current assets		(4,874)		(4,874)
Total assets		(4,874)		(4,874)
Contract liabilities	[2]	1,754		1,754
Total current liabilities		1,754		1,754
Deferred tax liabilities		(1,122)		(1,122)
Total liabilities		631		631
Retained earnings		(5,505)		(5,505)
Total shareholders' equity		(5,505)		(5,505)
Total liabilities and shareholders' equity		(4,874)		(4,874)
Consolidated Statements of Operations
Net sales		(2,879)		(5,779)
Cost of sales		(3,719)		(6,981)
Total costs and expenses		(3,719)		(6,981)
Earnings before income tax		839		1,201
Income tax (benefit) expense		117		228
Net earnings		$ 723		$ 973
Basic:
Net earnings		$ 0.02		$ 0.04
Diluted:
Net earnings		$ 0.03		$ 0.04
Consolidated Statements of Comprehensive Income
Net earnings		$ 723		$ 973
Comprehensive income		723		973
Consolidated Statements of Cash flows
Net earnings		723		973
Adjustments to reconcile net earnings to net cash provided by operating activities:
Change in assets and liabilities				(973)
Net cash provided by operating activities				0
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Consolidated Balance Sheets
Contract assets	[1]	60,975		60,975
Inventories		159,185		159,185
Total current assets		431,085		431,085
Total assets		1,289,089		1,289,089
Contract liabilities	[2]	57,207		57,207
Total current liabilities		203,699		203,699
Deferred tax liabilities		61,816		61,816
Total liabilities		500,198		500,198
Retained earnings		637,513		637,513
Total shareholders' equity		788,891		788,891
Total liabilities and shareholders' equity		1,289,089		1,289,089
Consolidated Statements of Operations
Net sales		191,070		370,767
Cost of sales		118,227		233,873
Total costs and expenses		168,875		324,953
Earnings before income tax		22,194		45,813
Income tax (benefit) expense		2,675		8,726
Net earnings		$ 19,520		$ 37,087
Basic:
Net earnings		$ 0.75		$ 1.43
Diluted:
Net earnings		$ 0.75		$ 1.42
Consolidated Statements of Comprehensive Income
Net earnings		$ 19,520		$ 37,087
Comprehensive income		20,323		33,336
Consolidated Statements of Cash flows
Net earnings		$ 19,520		37,087
Adjustments to reconcile net earnings to net cash provided by operating activities:
Change in assets and liabilities				(29,820)
Net cash provided by operating activities				$ 16,992

[1] Previously “cost and estimated earnings on long-term contracts”

[2] Previously “advance payments on long-term contracts” and “current portion of deferred revenue”