Fair Value Measurements (Narrative) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Long-term Debt gross	$ 585,222,000	$ 604,142,000
Fixed Interest Rate [Member]
Long-term Debt gross	345,253,000
Long-term Debt, Fair Value	365,111,000
Variable Interest Rate [Member]
Long-term Debt gross	239,969,000
Long-term Debt, Fair Value	239,969,000
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Supplemental executive retirement savings plan investments - Level 2	$ 16,175,000	$ 13,313,000