Derivative Instruments, Hedging Activities and Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2012
Derivative Instruments, Hedging Activities and Accumulated Other Comprehensive Income [Abstract]
Notional amount of cash flow hedges	$ 161,500
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income, net of tax	1,122
Accumulated Other Comprehensive Income, net of tax	541
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Amount of notional principal interest rate swap			$ 174,600
Gains and (Losses) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), before Tax	1,871
Other comprehensive loss before reclassifications, before tax	(1,771)
Amounts reclassified from accumulated other comprehensive income (to interest expense), before tax	798
Net current period other comprehensive loss, before tax	(973)
Accumulated Other Comprehensive Income (Loss), before Tax	898
Accumulated Other Comprehensive Income Loss, Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), tax	(749)
Other comprehensive income before reclassifications, tax	711
Amounts reclassified From accumulated other comprehensive income (to interest expense), tax	(319)
Net current period other comprehensive loss	392
Accumulated Other Comprehensive Income (Loss), tax	(357)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income, net of tax	1,122
Other comprehensive income before reclassifications, net of tax	(1,060)
Amounts reclassified from accumulated other comprehensive income (to interest expense), net of tax	479
Net current period other comprehensive income (loss), net of tax	(581)
Accumulated Other Comprehensive Income, net of tax	541
Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount reclassified as an increase to interest expense during next twelve months	1,200
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	898	$ 1,871
Designated as Hedging Instrument [Member] | Accrued Liabilities and Other [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivatives Liabilities, Fair Value	(1,167)	(1,309)
Designated as Hedging Instrument [Member] | Deferred Charges and Other Assets, Net [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Fair Value	$ 2,065	$ 3,180