Debt (Credit Facility) (Details) (USD $)	0 Months Ended
	Aug. 01, 2013
Line of Credit Facility [Line Items]
Credit facility borrowing capacity	$ 310,000,000
Term loan amount	50,000,000
Debt term	5 years
Fees and legal expenses	1,700,000
Basis spread on borrowings variable rate	1.95%
Weighted-average interest rate	2.20%
Additional borrowing capacity under accordion feature	500,000,000
Term loan, amount outstanding	50,000,000
Remaining borrowing capacity	106,800,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity	260,000,000
Debt term	3 years
Revolving credit facility, amount outstanding	$ 130,000,000
Minimum [Member]
Line of Credit Facility [Line Items]
Basis spread on borrowings variable rate	1.65%
Maximum [Member]
Line of Credit Facility [Line Items]
Basis spread on borrowings variable rate	2.25%