Fair Value Measurements (Fair Value Assets (Liabilities) Measured On Recurring Basis) (Details) - Fair Value Measurements Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonqualified savings plan-related assets and director deferred shares	$ 10,767	$ 12,838
Investment in equity securities	42,613	131,584
Total	53,380	144,422
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonqualified savings plan-related assets and director deferred shares	10,767	12,259
Investment in equity securities	42,613	0
Total	53,380	12,259
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonqualified savings plan-related assets and director deferred shares	0	579
Investment in equity securities	0	131,584
Total	0	132,163
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonqualified savings plan-related assets and director deferred shares	0	0
Investment in equity securities	0	0
Total	$ 0	$ 0