CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Beginning Balance, Shares at Dec. 31, 2016	326,688,000
Beginning Balance at Dec. 31, 2016	$ 326,688		$ 77,452	$ (70,075)	$ 234,480	$ 568,545
Net Income					179,124	179,124
Other comprehensive income
Pension liability adjustment, net of tax				14,159		14,159
Foreign currency translation adjustments				9,960		9,960
Cash dividends					(122,017)	(122,017)
Stock compensation	$ 651		11,965		(217)	12,399
Stock compensation, Shares	651,000
Employee stock buybacks	$ (351)		(8,012)		117	(8,246)
Employee stock buybacks, Shares	(351,000)
Ending Balance, Shares at Dec. 31, 2017	326,988,000
Ending Balance at Dec. 31, 2017	$ 326,988		81,405	(45,956)	291,487	653,924
Other comprehensive income
Interest rate swaps, net of tax
Net Income					231,663	231,663
Pension liability adjustment, net of tax				(11,050)		(11,050)
Foreign currency translation adjustments				(14,072)		(14,072)
Cash dividends					(152,742)	(152,742)
Stock compensation	$ 605		13,323		(202)	13,726
Stock compensation, Shares	605,000
Employee stock buybacks	$ (285)		(9,342)		86	(9,541)
Employee stock buybacks, Shares	(285,000)
Ending Balance, Shares at Dec. 31, 2018	327,308,000
Ending Balance at Dec. 31, 2018	$ 327,308		85,386	(71,078)	370,292	711,908
Other comprehensive income
Interest rate swaps, net of tax
Net Income					203,347	203,347
Pension liability adjustment, net of tax				(126)		(126)
Foreign currency translation adjustments				4,350		4,350
Cash dividends					(153,836)	(153,836)
Stock compensation	$ 387		13,772			14,159
Stock compensation, Shares	387,000
Employee stock buybacks	$ (264)		(9,745)			(10,009)
Employee stock buybacks, Shares	(264,000)
Ending Balance, Shares at Dec. 31, 2019	327,431,000
Ending Balance at Dec. 31, 2019	$ 327,431		$ 89,413	(21,109)	420,015	815,750
Other comprehensive income
Impact of adoption of ASC 842					$ 212	212
Pension settlement loss, net of tax				46,022		46,022
Interest rate swaps, net of tax				$ (277)		$ (277)