Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Attributable to Parent	$ 16,588	$ 14,879
Weighted Average Number of Shares Outstanding, Basic	86,475	90,689
Earnings Per Share, Basic	$ 0.19	$ 0.16
Dilutive Securities, Effect on Basic Earnings Per Share, Including Options and Restrictive Stock Units	0
Incremental Common Shares Attributable to Share-based Payment Arrangements	351
Net Income (Loss) Available to Common Stockholders, Diluted	$ 16,588
Weighted Average Number of Shares Outstanding, Diluted	86,826	90,689
Earnings Per Share, Diluted	$ 0.19	$ 0.16