ACCOUNTS RECEIVABLE (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Components of accounts receivable under long-term contracts
Total accounts receivable under long-term contracts	$ 381,329				$ 353,809
Less estimated amounts not currently due	(19,021)	(19,698)	(20,678)	(21,308)	(21,918)	(22,774)	(23,514)	(24,064)
Accounts receivable under long-term contracts, current	362,308				331,891
U.S. government contracts
Components of accounts receivable under long-term contracts
Amounts billed	51,529				42,852
Recoverable costs and accrued profits on progress completed--not billed	60,435				77,750
Total accounts receivable under long-term contracts	111,964				120,602
Commercial customers
Components of accounts receivable under long-term contracts
Amounts billed	47,454				48,280
Recoverable costs and accrued profits on progress completed--not billed	221,911				184,927
Total accounts receivable under long-term contracts	263,918				233,207
Less estimated amounts not currently due	$ (19,021)				$ (21,918)