Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Derivative Instrument [Line Items]
Derivative, Notional Amount	$ 150,000
Derivative, Maturity Date	Jul. 13, 2014
Derivative, Inception Date	Jul. 13, 2011
DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNetIncomeTaxNet	789
Derivative Liability, Fair Value, Gross Liability	$ 1,396
July 2011 agreement [Member]
Derivative Instrument [Line Items]
Derivative, Basis Spread on Variable Rate	5.50%
Derivative, Fixed Interest Rate	1.983%
DerivativeFixedInterestRateTotal	7.483%
Interest rate floor on Eurodollar loan	1.50%
August 2012 amendment [Member]
Derivative Instrument [Line Items]
Derivative, Basis Spread on Variable Rate	4.50%
Derivative, Fixed Interest Rate	1.783%
DerivativeFixedInterestRateTotal	6.283%
Interest rate floor on Eurodollar loan	1.25%