Long Term Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Components of Long-term Debt

The components of long-term debt as of December 31 are as follows:

	December 31, 2016				December 31, 2015
			Unamortized				Unamortized
			Debt				Debt
			Issuance				Issuance
	Principal		Debt Cost		Principal		Debt Cost
	(Thousands of dollars)
Senior Notes issued March 17, 2014, interest only payable semi-annually at 5.25%, maturing March 15, 2019	$	500,000	$	2,753	$	500,000	$	3,999
Revolving Credit Facility due October 1, 2018 with a group of commercial banks, interest payable at variable rates		134,000		—		57,500		—
Total long-term debt	$	634,000	$	2,753	$	557,500	$	3,999

Summary of Annual Maturities of Long-term Debt

Listed below is information on our future annual maturities of long-term debt (in thousands):

2017	$	—
2018		134,000
2019		500,000
2020		—
2021		—
Thereafter		—
Total	$	634,000