CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - 6 months ended Jun. 30, 2017 - USD ($) $ in Thousands	Total	Common Stock and Additional Paid-In Capital	Retained Earnings	Cumulative Translation Adjustment	Retirement Benefits Adjustment	Cumulative Unrealized Gain (Loss) on Derivatives	Treasury Stock
Balance, December 31, 2016 at Dec. 31, 2016	$ 1,543,894	$ 698,115	$ 1,834,739	$ (155,544)	$ (27,852)	$ (18,257)	$ (787,307)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	159,743		159,743
Cumulative translation adjustment	68,364			68,364
Net change in retirement obligations (net of tax of $1,146)	2,404				2,404
Net change on derivatives designated as cash flow hedges (net of tax of $1,218)	2,105					2,105
Issuance of 335,902 shares of common stock from issuance of unvested shares, performance share units and exercise of stock options (net of tax of $4,998)	12,984						12,984
Repurchase of 106,000 shares of common stock	(9,799)						(9,799)
Unvested shares surrendered for tax withholding	(5,814)						(5,814)
Share-based compensation	10,255	10,255
Cash dividends declared - $0.74 per common share outstanding	57,125		57,125
Balance, June 30, 2017 at Jun. 30, 2017	$ 1,727,011	$ 708,370	$ 1,937,357	$ (87,180)	$ (25,448)	$ (16,152)	$ (789,936)