Debt (details textuals 2) (USD $) In Millions, unless otherwise specified	12 Months Ended		0 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Apr. 18, 2012 Twenty Twelve Senior Secured Credit Facility Revolver [Member]	Apr. 18, 2012 Twenty Twelve Senior Secured Credit Facility Term Loan [Member]	Apr. 18, 2012 Twenty Twelve Senior Secured Credit Facility [Member]
Subsequent Events [Line Items]
Maturity Date 2012 Senior Secured Credit Facility Term					Apr. 18, 2019
Maturity Date 2012 Senior Secured Credit Facility Revolver			Apr. 18, 2017
Margin On Base Rate Borrowing On 2012 Senior Secured Credit Facility Term Current				2.00%
Margin On Libor Borrowing On 2012 Senior Secured Credit Facility Term Current				3.00%
Margin On Libor Borrowing On 2012 Senior Secured Credit Facility Term Step Down				2.75%
Margin On Base Rate Borrowing On 2012 Senior Secured Credit Facility Term Step Down				1.75%
Twenty Twelve Senior Secured Credit Facility Effective Step Down Date Term				Dec. 31, 2012
Senior Secured Debt to EBITDA Ratio Required For Step Down				1.01
Senior Secured Credit Facility Term Libor Floor				0.75%
Deferred Finance Charge For Debt Extinguishment	$ 9.5
Maximum Borrowing Capacity					1,200.0
Line of Credit Facility, Maximum Borrowing Capacity			650.0
Secured Debt	$ 543.4	$ 561.9		$ 550.0