Financing Activity (Tables)

3 Months Ended

Mar. 31, 2018

Debt Disclosure [Abstract]

Schedule of credit facility interest expense [Table Text Block]

		Three Months Ended   March 31,
(in thousands of dollars)		2018		2017
2013 Revolving Facility
	Interest expense	$	365	$	764
	Deferred financing amortization	200		199
Term Loans
	Interest expense	4,286		2,835
	Deferred financing amortization	191		187

Applicable Credit Spread Over Libor at Various Leverage Levels

		Applicable Margin
Level	Ratio of Total Liabilities to Gross Asset Value	2013 Revolving Facility	Term Loans
1	Less than 0.450 to 1.00	1.20%	1.35%
2	Equal to or greater than 0.450 to 1.00 but less than 0.500 to 1.00	1.25%	1.45%
3	Equal to or greater than 0.500 to 1.00 but less than 0.550 to 1.00 (1)	1.30%	1.60%
4	Equal to or greater than 0.550 to 1.00	1.55%	1.90%

Carrying and Fair Values of Mortgage Loans

The aggregate carrying values and estimated fair values of mortgage loans based on interest rates and market conditions at March 31, 2018 and December 31, 2017 were as follows:

	March 31, 2018				December 31, 2017
(in millions of dollars)	Carrying Value		Fair Value		Carrying Value		Fair Value
Mortgage loans(1)	$	1,062.1	$	1,023.0	$	1,056.1	$	1,029.7