Supplemental Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2019

Supplemental Cash Flow Elements [Abstract]

Supplemental Cash Flow Information

	Year Ended December 31,
	2019		2018		2017
	(in millions of dollars)
Interest paid	$	23.6	$	21.6	$	21.1
Non-cash investing and financing activities (included in Accounts payable):
Unpaid purchases of property and equipment	$	4.5	$	7.0	$	7.4
Stock repurchases not yet settled	$	—	$	1.3	$	0.1
Supplemental lease disclosures:
Operating lease liabilities arising from obtaining operating lease assets	$	1.8	n/a		n/a
Cash paid for amounts included in the measurement of operating lease liabilities	$	3.8	n/a		n/a
Finance lease liabilities arising from obtaining finance lease assets	$	1.0	$	6.5	$	1.2
	December 31,
	2019		2018		2017
Components of cash, cash equivalents and restricted cash:
Cash and cash equivalents	$	264.3	$	125.6	$	51.1
Restricted cash included in Prepaid expenses and other current assets	0.3		0.3		0.3
Restricted cash included in Other assets	14.0		13.7		12.9
Total cash, cash equivalents and restricted cash shown in the Statements of Consolidated Cash Flows	$	278.6	$	139.6	$	64.3