Long-Term Debt (Tables)

3 Months Ended

Mar. 31, 2013

Long-Term Debt [Abstract]

Components of long-term debt

	March 31, 2013		December 31, 2012
	(Thousands of dollars)
Senior Notes dated September 23, 2010, interest only payable semi-annually at 8.625%, maturing October 15, 2018	$	300,000	$	300,000
Revolving Credit Facility due September 1, 2014 with a group of commercial banks, interest payable at variable rates		79,155		86,755
Total long-term debt	$	379,155	$	386,755