Consolidated Statements of Equity Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid- In Capital	Retained Earnings	AOCI Attributable to Parent [Member]	Non Controlling Interest
Beginning balance (in shares) at Dec. 31, 2018		60,900
Beginning balance at Dec. 31, 2018	$ 867,000	$ 600	$ 808,000	$ 121,100	$ (63,000)	$ 300
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		200
Employee stock compensation	12,100		12,100
Deferred compensation	(1,800)		(1,500)	(300)
Proceeds from stock issuances under employee plans (in shares)		0
Proceeds from stock issuances under employee plans	3,200	$ 0	3,200
Cash dividends declared	(37,100)			(37,100)
Repurchase and retirement of common shares (in shares)		(100)
Repurchase and retirement of common shares	(6,200)	$ 0	(1,000)	(5,200)
Other activity	0			600	(600)
Net income	48,400			48,400
Other comprehensive loss	(6,100)				(6,100)
Ending balance (in shares) at Mar. 31, 2019		61,000
Ending balance at Mar. 31, 2019	879,500	$ 600	820,800	127,500	(69,700)	300
Beginning balance (in shares) at Dec. 31, 2018		60,900
Beginning balance at Dec. 31, 2018	867,000	$ 600	808,000	121,100	(63,000)	300
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	224,900
Ending balance (in shares) at Sep. 30, 2019		61,100
Ending balance at Sep. 30, 2019	1,013,200	$ 600	867,200	228,800	(83,600)	200
Beginning balance (in shares) at Mar. 31, 2019		61,000
Beginning balance at Mar. 31, 2019	879,500	$ 600	820,800	127,500	(69,700)	300
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		0
Employee stock compensation	22,100		22,100
Deferred compensation	(1,800)		(1,200)	(600)
Proceeds from stock issuances under employee plans (in shares)		100
Proceeds from stock issuances under employee plans	3,000	$ 0	3,000
Cash dividends declared	(37,300)			(37,300)
Repurchase and retirement of common shares (in shares)		0
Repurchase and retirement of common shares	(400)	$ 0	(100)	(300)
Net income	88,100			88,200		(100)
Other comprehensive loss	(1,100)				(1,100)
Ending balance (in shares) at Jun. 30, 2019		61,100
Ending balance at Jun. 30, 2019	952,100	$ 600	844,600	177,500	(70,800)	200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		0
Employee stock compensation	22,300		22,300
Deferred compensation	(1,000)		(1,600)	600
Proceeds from stock issuances under employee plans (in shares)		0
Proceeds from stock issuances under employee plans	2,000	$ 0	2,000
Cash dividends declared	(37,300)			(37,300)
Repurchase and retirement of common shares (in shares)		0
Repurchase and retirement of common shares	(500)	$ 0	(100)	(400)
Net income	88,400			88,400		0
Other comprehensive loss	(12,800)				(12,800)
Ending balance (in shares) at Sep. 30, 2019		61,100
Ending balance at Sep. 30, 2019	1,013,200	$ 600	867,200	228,800	(83,600)	200
Beginning balance (in shares) at Dec. 31, 2019		61,400
Beginning balance at Dec. 31, 2019	1,108,200	$ 600	892,800	287,300	(72,700)	200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		400
Employee stock compensation	11,900	$ 0	11,900
Deferred compensation	6,900		(500)	7,400
Proceeds from stock issuances under employee plans (in shares)		0
Proceeds from stock issuances under employee plans	2,300		2,300
Cash dividends declared	(38,000)			(38,000)
Repurchase and retirement of common shares (in shares)		(600)
Repurchase and retirement of common shares	(48,800)	$ 0	(8,100)	(40,700)
Net income	(5,400)			(5,400)		0
Other comprehensive loss	(35,300)				(35,300)
Ending balance (in shares) at Mar. 31, 2020		61,200
Ending balance at Mar. 31, 2020	1,001,800	$ 600	898,400	210,600	(108,000)	200
Beginning balance (in shares) at Dec. 31, 2019		61,400
Beginning balance at Dec. 31, 2019	$ 1,108,200	$ 600	892,800	287,300	(72,700)	200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase and retirement of common shares (in shares)	(600)
Repurchase and retirement of common shares	$ (49,500)
Net income	(73,900)
Ending balance (in shares) at Sep. 30, 2020		61,700
Ending balance at Sep. 30, 2020	947,800	$ 600	972,800	59,000	(84,900)	300
Beginning balance (in shares) at Mar. 31, 2020		61,200
Beginning balance at Mar. 31, 2020	1,001,800	$ 600	898,400	210,600	(108,000)	200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		0
Employee stock compensation	19,800	$ 0	19,800
Deferred compensation	(7,500)		(1,400)	(6,100)
Proceeds from stock issuances under employee plans (in shares)		100
Proceeds from stock issuances under employee plans	4,600		4,600
Cash dividends declared	(38,000)			(38,000)
Repurchase and retirement of common shares (in shares)		0
Repurchase and retirement of common shares	(500)	$ 0	(100)	(400)
Net income	(235,400)			(235,400)		0
Other comprehensive loss	8,400				8,400
Ending balance (in shares) at Jun. 30, 2020		61,300
Ending balance at Jun. 30, 2020	753,200	$ 600	921,300	(69,300)	(99,600)	200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		0
Employee stock compensation	27,700	$ 0	27,700
Deferred compensation	(2,000)		(1,900)	(100)
Proceeds from stock issuances under employee plans (in shares)		400
Proceeds from stock issuances under employee plans	25,700		25,700
Cash dividends declared	(38,200)			(38,200)
Repurchase and retirement of common shares (in shares)		0
Repurchase and retirement of common shares	(200)	$ 0	0	(200)
Net income	166,900			166,800		100
Other comprehensive loss	14,700				14,700
Ending balance (in shares) at Sep. 30, 2020		61,700
Ending balance at Sep. 30, 2020	$ 947,800	$ 600	$ 972,800	$ 59,000	$ (84,900)	$ 300