Derivatives (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended
	Jun. 30, 2013	Feb. 28, 2011	Feb. 03, 2011
Forward starting interest rate swap, One [Member]
Summary of notional amount, effective dates and maturity dates
Notional Amount	$ 75,000		$ 75,000
Effective Date	Aug. 01, 2013	Mar. 01, 2012
Maturity	Aug. 01, 2014	Sep. 01, 2012
Forward starting interest rate swap, Two [Member]
Summary of notional amount, effective dates and maturity dates
Notional Amount	75,000		75,000
Effective Date	Aug. 01, 2014	Sep. 04, 2012
Maturity	Aug. 03, 2015	Sep. 01, 2013
Forward starting interest rate swap, Three [Member]
Summary of notional amount, effective dates and maturity dates
Notional Amount	75,000		75,000
Effective Date	Aug. 03, 2015	Sep. 03, 2013
Maturity	Aug. 01, 2016	Sep. 01, 2014
Forward starting interest rate swap, Four [Member]
Summary of notional amount, effective dates and maturity dates
Notional Amount	75,000		75,000
Effective Date	Aug. 01, 2016	Sep. 02, 2014
Maturity	Aug. 01, 2017	Sep. 01, 2015
Forward starting interest rate swap Five [Member]
Summary of notional amount, effective dates and maturity dates
Notional Amount			$ 75,000
Effective Date		Sep. 01, 2015
Maturity		Mar. 01, 2017