EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income	$ 86,839	[1]	$ 70,539	[2]	$ 68,864	[3]	$ 60,824	[4]	$ 24,181	[1]	$ 106,126	[2]	$ 61,352	[3]	$ 55,844	[4]	$ 287,066	$ 247,503	$ 198,399
Denominator:
Basic weighted average shares outstanding (in shares)																	64,886,000	65,739,000	67,462,000
Effect of dilutive securities - stock options and awards (in shares)																	796,000	904,000	694,000
Diluted weighted average shares outstanding (in shares)																	65,682,000	66,643,000	68,156,000
Basic earnings per share (in dollars per share)	$ 1.36	[5]	$ 1.09	[5]	$ 1.05	[5]	$ 0.93	[5]	$ 0.37	[5]	$ 1.61	[5]	$ 0.93	[5]	$ 0.85	[5]	$ 4.42	$ 3.76	$ 2.94
Diluted earnings per share (in dollars per share)	$ 1.35	[5]	$ 1.07	[5]	$ 1.04	[5]	$ 0.92	[5]	$ 0.36	[5]	$ 1.59	[5]	$ 0.92	[5]	$ 0.84	[5]	$ 4.37	$ 3.71	$ 2.91
Anti-dilutive shares excluded from the computation of diluted earnings per share																	324,688	157,033	774,502

[1] 2018 includes special item charges of $1,696 ($1,272 after-tax) for pension settlement charges, $932 ($841 gain after-tax) for rationalization and asset impairment charges and gains or losses on the disposal of assets, a $4,424 credit related to the U.S. Tax Act and acquisition-related items including $833 ($690 after-tax) for acquisition transaction and integration costs. 2017 includes special item charges of $2,867 ($1,770 after-tax) for pension settlement charges, $6,590 ($6,198 after-tax) for rationalization and asset impairment charges, $28,616 for the net impact of the U.S. Tax Act and acquisition-related items including $2,264 ($1,708 after-tax) in amortization of step up in value of acquired inventories, $3,616 ($3,102 after-tax) for acquisition transaction and integration costs and a $1,935 adjustment to the bargain purchase gain

[2] 2018 includes special item charges of $4,232 ($3,176 after-tax) for pension settlement charges, $2,636 ($2,575 after-tax) for rationalization and asset impairment charges, an adjustment to taxes on unremitted foreign earnings related to the U.S. Tax Act of $2,323 and acquisition-related items including $970 ($797 after-tax) for acquisition transaction and integration costs.2017 includes special item charges of $5,283 ($3,260 after-tax) for pension settlement charges and acquisition-related items including $2,314 ($1,745 after-tax) in amortization of step up in value of acquired inventories, $3,273 ($2,229 after-tax) for acquisition transaction and integration costs and a $51,585 bargain purchase gain

[3] 2018 includes special item charges of $11,542 ($10,362 after-tax) for rationalization and asset impairment charges and $788 ($675 after-tax) for acquisition transaction and integration costs.2017 includes special item charges of $4,498 ($3,494 after-tax) related to acquisition transaction and integration costs

[4] 2018 includes special item charges of $758 ($569 after-tax) for pension settlement charges, $10,175 ($7,870 after-tax) for rationalization and asset impairment charges, an adjustment to taxes on unremitted foreign earnings related to the U.S. Tax Act of $2,500 and $1,907 ($1,520 after-tax) for acquisition transaction and integration costs.2017 includes special item charges of $3,615 ($2,734 after-tax) related to acquisition transaction costs.

[5] The quarterly earnings per share ("EPS") amounts are each calculated independently. Therefore, the sum of the quarterly EPS amounts may not equal the annual totals.