Stockholders Equity and Equity Compensation Plans (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stockholders Equity and Equity Compensation Plans (Additional Textual) [Abstract]
Shares repurchased				500,000	800,000
Total amount paid				$ 10.1	$ 13.3
Weighted-average price per share				$ 20.23	$ 16.23
Remaining number of shares available for repurchase	2,100,000			2,100,000
Repurchase of common stock for employee tax withholdings, shares				300,000	200,000
Repurchase of common stock for tax withholdings, value				5.0	3.0
Cash dividends declared per common share	$ 0.15	$ 0.15		$ 0.30
Cash dividend	5.1	5.1
Payment of cash dividends	4.8	4.8
Date of Dividend Approval	Aug. 22, 2013	Jun. 25, 2013
Shareholders of Record Date	Sep. 10, 2013	Jul. 10, 2013
Dividend payment date	Sep. 25, 2013	Jul. 25, 2013
Performance based awards granted to executive management shares				175,384
Stock-based compensation expense	$ 4.0		$ 3.5	$ 11.5	$ 10.0
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