Condensed Consolidated Statements Of Shareholders' Equity (USD $) In Thousands, except Share data	Common Shares [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Shares [Member]	Total
Balances, value at Dec. 31, 2011	$ 5,779	$ 674,498	$ 449,193	$ (13,450)	$ (272)	$ 1,115,748
Balances, shares at Dec. 31, 2011	57,791,000					57,791,000
Stock-based compensation expense		3,050				3,050
Shares repurchased and retired, shares	(1,615,000)
Shares repurchased and retired, value	(162)	(17,356)	(5,774)			(23,292)
Stock options exercised, shares	192,000					192,000
Stock options exercised, value	20	2,236				2,256
Issuance of restricted shares, net of forfeitures, shares	213,000
Issuance of restricted shares, net of forfeitures, value	21	(21)
Excess tax shortfall of stock-based compensation		(120)				(120)
Comprehensive income (loss)			19,178	(381)		18,797
Balances, value at Jun. 30, 2012	$ 5,658	$ 662,287	$ 462,597	$ (13,831)	$ (272)	$ 1,116,439
Balances, shares at Jun. 30, 2012	56,581,000					56,581,000