REVENUE DISAGGREGATION OF REVENUE (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Net Sales	$ 668,444	$ 571,614	$ 550,047	$ 601,231	$ 655,771	$ 614,880	$ 638,996	$ 578,314	$ 2,391,336	$ 2,487,961	$ 2,411,835
Defense
Disaggregation of Revenue [Line Items]
Net Sales									1,263,290	1,079,049	960,558
Commercial [Member]
Disaggregation of Revenue [Line Items]
Net Sales									1,128,046	1,408,912	1,451,277
Defense Aerospace [Member] | Defense
Disaggregation of Revenue [Line Items]
Net Sales									463,835	416,841	376,951
Defense Ground [Member] | Defense
Disaggregation of Revenue [Line Items]
Net Sales									107,287	93,432	97,131
Naval [Member] | Defense
Disaggregation of Revenue [Line Items]
Net Sales									692,168	568,776	486,476
Commercial Aerospace [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Net Sales									325,518	433,038	414,422
Power Generation [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Net Sales									331,983	392,173	431,793
General Industrial [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Net Sales									$ 470,545	$ 583,701	$ 605,062
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue, Net, Percent									52.00%	49.00%	46.00%
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue, Net, Percent									48.00%	51.00%	54.00%