SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES – Adoption of ASU 2017-07 (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales	$ 464,244	$ 399,664	$ 920,066	$ 784,348
Selling, research & development and administrative	107,111	95,456	219,572	196,738
Total Operating Expenses	629,670	532,362	1,245,064	1,055,659
Operating Income	80,938	85,384	168,894	163,403
Miscellaneous, net	(577)	1,275	(1,444)	716
Total Other (Expense) Income	(6,040)	(5,816)	(12,779)	(14,355)
Income before Income Taxes	$ 74,898	79,568	$ 156,115	149,048
Original Balance | Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales		399,954		784,886
Selling, research & development and administrative		95,659		197,175
Total Operating Expenses		532,855		1,056,634
Operating Income		84,891		162,428
Miscellaneous, net		1,768		1,691
Total Other (Expense) Income		(5,323)		(13,380)
Income before Income Taxes		79,568		149,048
Adjustment | Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales		(290)		(538)
Selling, research & development and administrative		(203)		(437)
Total Operating Expenses		(493)		(975)
Operating Income		493		975
Miscellaneous, net		(493)		(975)
Total Other (Expense) Income		$ (493)		$ (975)