Consolidated Statement of Changes in Equity (unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Shares Held in Trust [Member]	Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Balances at Dec. 31, 2012	$ 1,959,256	$ 441	$ 932,255	$ 1,017,128	$ (7,587)	$ 8,946	$ 8,073
Balances (in shares) at Dec. 31, 2012		44,054,042
Increase (decrease) in shareholders' equity [Roll Forward]
Net income	125,829			122,543			3,286
Shares issued under stock compensation programs (in shares)		535,529
Shares issued under stock compensation programs	1,062	5	1,057
Shares repurchased for payment of taxes on stock awards (in shares)		(154,854)
Shares repurchased for payment of taxes on stock awards	(14,080)	(2)	(14,078)
Tax adjustments due to vestings and exercises	3,421		3,421
Amortization of stock compensation	18,148		18,148
Dividends paid, $0.22 per share	(10,023)			(10,023)
Shares held in trust	(465)				(465)
Decrease in amount attributable to noncontrolling interest	(4,361)						(4,361)
Foreign currency translation adjustments	(45,357)					(45,357)
Balances at Sep. 30, 2013	$ 2,033,430	$ 444	$ 940,803	$ 1,129,648	$ (8,052)	$ (36,411)	$ 6,998
Balances (in shares) at Sep. 30, 2013		44,434,717