Shareholders' Equity Shareholders' Equity (Details textual) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	0 Months Ended	6 Months Ended		6 Months Ended	3 Months Ended	1 Months Ended		6 Months Ended
	Jun. 08, 2013	Jun. 30, 2013	Feb. 06, 2013	Jun. 30, 2013 Common Stock and Additional Paid-in Capital	Jun. 30, 2013 Retained Earnings	Apr. 30, 2013 Accelerated share repurchase program [Member] Common Stock and Additional Paid-in Capital	Mar. 31, 2013 Accelerated share repurchase program [Member] Common Stock and Additional Paid-in Capital	Jun. 30, 2013 Accelerated share repurchase program [Member] Common Stock and Additional Paid-in Capital
Stockholders Equity Note [Line Items]
Common stock repurchased, shares				1.6		0.3	2.6
Stock Repurchased During Period, Value		$ 116,830,000						$ 75,000,000
Common stock authorized to be repurchased, number of shares (in shares)			25.0
Common stock dividends, paid per share (in dollars per share)	$ 0.09
Common stock dividends, total cash paid					$ 25,900,000