Subsequent Event (Details)	9 Months Ended
	Sep. 30, 2015 USD ($)	Oct. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jul. 31, 2013 USD ($)
Subsequent Event [Line Items]
Initial maximum financial leverage ratio	3.25
Minimum permitted fixed charge coverage ratio	1.25
2015 Credit Facility [Member]
Subsequent Event [Line Items]
Term of credit facility	5 years
Debt Instrument, Term	5 years
2015 Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Permitted Additional Borrowings		$ 250,000,000
Credit Facility Maximum Consolidated Leverage Ratio, Scheduled Decrease		3.50
Debt Instrument, Face Amount		$ 650,000,000
Maximum borrowing capacity		300,000,000
Secured Debt		350,000,000
Debt Instrument, Fee Amount		4,400,000
Derivative, Amount of Hedged Item		$ 262,500,000
Initial maximum financial leverage ratio		3.75
Minimum permitted fixed charge coverage ratio		1.25
2013 Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount				$ 650,000,000
Maximum borrowing capacity				300,000,000
Term of credit facility	5 years
Secured Debt	$ 273,200,000		$ 319,400,000	350,000,000
Debt Instrument, Term	5 years
Derivative, Amount of Hedged Item				$ 175,000,000
2013 Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount		$ 344,700,000
LIBOR [Member] | 2015 Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Interest rate at period end		2.19%
LIBOR [Member] | 2013 Credit Facility [Member]
Subsequent Event [Line Items]
Interest rate at period end	2.06%
LIBOR [Member] | Minimum [Member] | 2015 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	1.25%
LIBOR [Member] | Minimum [Member] | 2013 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	1.25%
LIBOR [Member] | Maximum [Member] | 2015 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	2.25%
LIBOR [Member] | Maximum [Member] | 2013 Credit Facility [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	2.25%
2015 Interest Rate Swap [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Derivative, Fixed Interest Rate		1.46%
Derivative Asset, Notional Amount		$ 262,500,000
Derivative, Variable Interest Rate		3.46%