CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Shares	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non-controlling Interest
Beginning balance (in shares) at Dec. 31, 2016		122,904,368
Beginning balance at Dec. 31, 2016	$ 1,496,752	$ 709,867	$ 700,887	$ 856	$ 85,142
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	161,579		148,842		12,737
Dividends	(127,986)		(127,986)
Issuance of shares under incentive stock plans, (in shares)		322,314
Issuance of shares under incentive stock plans	4,751	$ 4,751
Stock-based compensation	5,396	$ 5,396
Repurchase of common shares, (in shares)		(5,906)
Repurchase of common shares	(176)	$ (176)
Actuarial change and amortization of pension and postretirement plan liabilities	(208)			(208)
Foreign currency translation adjustment	9,114			7,416	1,698
Cash flow hedges	5,693			5,353	340
Issuance of shares under equity offering, net of costs (in shares)		5,750,000
Issuance of shares under equity offering, net of costs	152,390	$ 152,390
Ending balance (in shares) at Dec. 31, 2017		128,970,776
Ending balance at Dec. 31, 2017	1,692,940	$ 872,228	707,378	13,417	99,917
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	117,330		102,216		15,114
Dividends	(137,934)		(137,934)
Issuance of shares under incentive stock plans, (in shares)		599,422
Issuance of shares under incentive stock plans	8,591	$ 8,591
Stock-based compensation	6,428	$ 6,428
Repurchase of common shares, (in shares)		(81,523)
Repurchase of common shares	(2,984)	$ (2,984)
Actuarial change and amortization of pension and postretirement plan liabilities	(919)			(919)
Foreign currency translation adjustment	(22,759)			(17,329)	(5,430)
Cash flow hedges	5,029			5,781	(752)
Distribution to minority shareholder	(11,172)				(11,172)
Ending balance (in shares) at Dec. 31, 2018		129,488,675
Ending balance at Dec. 31, 2018	1,654,550	$ 884,263	672,371	239	97,677
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	67,678		59,105		8,573
Dividends	(140,040)		(140,040)
Issuance of shares under incentive stock plans, (in shares)		298,003
Issuance of shares under incentive stock plans	1,260	$ 1,260
Stock-based compensation	6,904	$ 6,904
Repurchase of common shares, (in shares)		(455,609)
Repurchase of common shares	(12,680)	$ (4,250)	(8,430)
Actuarial change and amortization of pension and postretirement plan liabilities	(1,350)			(1,350)
Foreign currency translation adjustment	963			784	179
Cash flow hedges	(30,482)			(30,875)	393
Distribution to minority shareholder	(9,161)				(9,161)
Ending balance (in shares) at Dec. 31, 2019		129,331,069
Ending balance at Dec. 31, 2019	$ 1,537,642	$ 888,177	$ 583,006	$ (31,202)	$ 97,661