Debt (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Short-term debt:
Bank Credit Facility	$ 38,000	$ 38,000
Long-term debt:
Final Maturity	2015
Long-term debt	199,874	199,809
Total	237,874	237,809
Senior Notes 2015 [Member]
Long-term debt:
Effective Interest Rates	6.10%
Final Maturity	2015
Long-term debt	74,962	74,935
Senior Notes 2016 [Member]
Long-term debt:
Effective Interest Rates	6.90%
Final Maturity	2016
Long-term debt	$ 124,912	$ 124,874