Debt Obligations (Narrative) (Details) (USD $)	3 Months Ended					3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Senior Secured Credit Facility [Member]	Mar. 31, 2014 Revolving Credit Facility [Member]	Aug. 18, 2011 Term Loan A [Member]	Mar. 31, 2014 Minimum [Member] LIBOR [Member]	Mar. 31, 2014 Minimum [Member] Base Rate [Member]	Mar. 31, 2014 Maximum [Member] LIBOR [Member]	Mar. 31, 2014 Maximum [Member] Base Rate [Member]	Jun. 30, 2014 Senior Secured Credit Facility [Member]	Apr. 09, 2014 Senior Secured Credit Facility [Member]	Apr. 09, 2014 Revolving Credit Facility [Member]	Apr. 09, 2014 Term Loan A [Member]
Debt Instrument [Line Items]
Borrowing capacity of revolving credit facility post amendment												$ 600,000,000
Debt Instrument, Basis Spread on Variable Rate						1.50%	0.50%	2.50%	1.50%
Revolving Credit Facility, Interest Rate at Period End	1.77%
Term Loan A, Weighted Average Interest Rate	1.65%
Term Loan A	66,000,000	68,000,000			80,000,000								75,000,000
Line of Credit Facility, Maximum Borrowing Capacity			$ 480,000,000	$ 400,000,000
Debt Instrument, Basis Spread Reduction											0.125%
Line of Credit Facility, Expiration Date	Aug. 18, 2016
Credit Facility Expiration Date - Amended Facility										Apr. 09, 2019