Accrued Expenses Accrued liabilities (Tables)

12 Months Ended

Dec. 31, 2015

Accrued Liabilities, Current [Abstract]

Schedule of Accrued Liabilities [Table Text Block]

December 31,	2015		2014
(Thousands of dollars)
Construction in progress	$	—	$	4,090
Payroll and related benefits	13,538		13,202
Current portion of derivative liability	9,629		5,598
Dividends	4,964		4,862
Taxes, other than income taxes	7,354		6,961
Current portion of executive retirement liabilities	1,524		1,507
Other	9,205		11,804
Accrued liabilities	$	46,214	$	48,024