Interest Rate Swap Agreements (Schedule of effect of Swaps on Comprehensive Income) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest Rate Swaps
Derivatives designated as hedging instruments:
Amount Recognized in Interest Expense (Pre-Tax)		$ 2,446	$ 0	$ 0
Amount of Loss/(Gain) Recognized in Other Comprehensive Income on Derivative (Effective Portion) (Pre-Tax)		(1,845)	865	$ 1,737
Recurring | Level 2 | Other accrued liabilities
Derivatives designated as hedging instruments:
Interest rate swaps	[1]	$ 1,762	2,375
Recurring | Level 2 | Other long-term liabilities
Derivatives designated as hedging instruments:
Interest rate swaps	[1]		$ 1,232

[1] The fair value is determined using valuation models which rely on the expected LIBOR based yield curve and estimates of counterparty and the Company’s non-performance risk. Because each of these inputs are directly observable or can be corroborated by observable market data, the Company has categorized these interest rate swaps as Level 2 within the fair value hierarchy.