Fair Value Measurements (Schedule Of Assets And Liabilities Measured At A Fair Value On Recurring Basis) (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments related to deferred compensation liabilities	$ 447,000	$ 539,000
Interest rate swaps asset	3,074,000
Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments related to deferred compensation liabilities	447,000	539,000
Deferred compensation liabilities	435,000	529,000
Interest rate swaps asset	3,074,000
Interest rate swaps liability	2,321,000	3,945,000
Recurring Basis [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments related to deferred compensation liabilities	447,000	539,000
Deferred compensation liabilities	435,000	529,000
Recurring Basis [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps asset	3,074,000
Interest rate swaps liability	$ 2,321,000	$ 3,945,000