CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - 3 months ended Mar. 31, 2016 - 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 at Dec. 31, 2015	$ 1,443,291	$ 680,525	$ 1,666,680	$ (92,979)	$ (30,901)	$ (22,618)	$ (757,416)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	68,130		68,130
Cumulative translation adjustment	16,217			16,217
Pension and other postretirement adjustments (net of tax of $322)	671				671
Amortization of forward starting swaps (net of tax of $627)	1,097					1,097
Issuance of 361,570 shares of common stock from issuance of restricted stock, performance share units and exercise of stock options	8,258						8,258
Repurchase of 628,493 shares of common stock	(45,790)						(45,790)
Shares surrendered for tax withholding	(4,717)						(4,717)
Share-based compensation	5,753	5,753
Balance at Mar. 31, 2016	$ 1,492,910	$ 686,278	$ 1,734,810	$ (76,762)	$ (30,230)	$ (21,521)	$ (799,665)