Debt - Line of Credit (Details) (Credit Agreement 2012 [Member], Refinancing of Debt [Member], USD $) In Millions, unless otherwise specified	Jan. 06, 2012
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 300
Line of Credit Facility, Available Additional Borrowing Capacity	$ 200
Adjusted Base Rate Advances [Member] | Adjusted Base Rate [Member] | Federal Funds Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Basis Spread on Variable Rate	0.50%
Adjusted Base Rate Advances [Member] | Adjusted Base Rate [Member] | Eurodollar Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Basis Spread on Variable Rate	1.00%
Adjusted Base Rate Advances [Member] | Applicable Margin [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Basis Spread on Variable Rate	0.125%
Adjusted Base Rate Advances [Member] | Applicable Margin [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Basis Spread on Variable Rate	0.75%
Eurodollar Advances [Member] | Applicable Margin [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Basis Spread on Variable Rate	1.125%
Eurodollar Advances [Member] | Applicable Margin [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Basis Spread on Variable Rate	1.75%