Stockholders Equity and Equity Compensation Plans (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Stockholders Equity and Equity Compensation Plans (Additional Textual) [Abstract]
Shares repurchased			500,000	700,000
Total amount paid			$ 10.0	$ 10.6
Weighted-average price per share			$ 20.21	$ 15.80
Remaining number of shares available for repurchase	2,100,000		2,100,000
Repurchase of common stock for employee tax withholdings, shares			200,000	200,000
Repurchase of common stock for tax withholdings, value			4.9	2.9
Performance based awards granted to executive management shares			175,384
Stock-based compensation expense	3.9	3.4	7.5	6.5
Cash dividends declared per common share	$ 0.15		$ 0.15
Cash dividend			$ 5.1
Performance Shares
Stockholders' Equity and Equity Compensation Plans (Textual) [Abstract]
Common stock shares issued to members of executive management vesting installments			3 years
Restricted common stock
Stockholders' Equity and Equity Compensation Plans (Textual) [Abstract]
Common stock shares issued to members of executive management vesting installments	4 years		4 years