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, 2017		63,075
Beginning balance at Dec. 31, 2017	$ 931,659	$ 631	$ 733,894	$ 242,763	$ (45,629)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		(5)
Employee stock compensation	12,032		12,032
Deferred compensation	420		(392)	812
Proceeds from stock issuances under employee plans (in shares)		161
Proceeds from stock issuances under employee plans	11,905	$ 2	11,903
Cash dividends declared	(37,796)			(37,796)
Repurchase and retirement of common shares (in shares)		(133)
Repurchase and retirement of common shares	(14,987)	$ (2)	(1,549)	(13,436)
Other activity	(1,077)			(1,077)
Net income	55,714			55,714
Other comprehensive loss	15,592				15,592
Ending balance (in shares) at Mar. 31, 2018		63,098
Ending balance at Mar. 31, 2018	973,462	$ 631	755,888	246,980	(30,037)	0
Beginning balance (in shares) at Dec. 31, 2017		63,075
Beginning balance at Dec. 31, 2017	931,659	$ 631	733,894	242,763	(45,629)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other activity		$ 0
Ending balance (in shares) at Dec. 31, 2018		60,890
Ending balance at Dec. 31, 2018	867,015	$ 609	807,986	121,114	(62,973)	279
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock compensation (in shares)		214
Employee stock compensation	12,091	$ 2	12,089
Deferred compensation	(1,887)		(1,541)	(346)
Proceeds from stock issuances under employee plans (in shares)		18
Proceeds from stock issuances under employee plans	3,207		3,207
Cash dividends declared	$ (37,144)			(37,144)
Repurchase and retirement of common shares (in shares)	(71)	(71)
Repurchase and retirement of common shares	$ (6,110)	$ 0	(953)	(5,157)
Other activity	0			668	(668)	0
Net income	48,396			48,378		18
Other comprehensive loss	(6,069)				(6,069)
Ending balance (in shares) at Mar. 31, 2019		61,051
Ending balance at Mar. 31, 2019	$ 879,499	$ 611	$ 820,788	$ 127,513	$ (69,710)	$ 297