Consolidated Condensed Statements of Cash Flows (Parenthetical) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Shares repurchased under the share repurchase program, value	$ 81,156	[1]
Stock Repurchase Authorization [Member] | Common Stock [Member]
Shares repurchased under the share repurchase program, value	77,900
Variable Prepaid Share Repurchase Agreement [Member] | Common Stock [Member]
Shares repurchased under the share repurchase program, value	$ 40,000

[1] 2013 includes $77.9 million repurchased under the share repurchase program launched in 2011 including $40.0 million associated with a prepaid variable share repurchase agreement.