Stock-Based Compensation

6 Months Ended

Jun. 30, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

Stock-Based Compensation

The following table summarizes the Company’s stock-based compensation expense (including stock options, restricted stock units (“RSUs”) and performance stock units (“PSUs”)) for the three and six months ended June 30, 2013 and 2012:

	Three Months Ended June 30,				Six Months Ended June 30,
(in millions of dollars)	2013		2012		2013		2012
Stock option compensation expense	$	0.8	$	0.5	$	1.4	$	0.8
RSU compensation expense	2.1		1.7		3.1		2.5
PSU compensation expense	2.2		0.2		2.9		0.8
Total stock-based compensation	$	5.1	$	2.4	$	7.4	$	4.1

During the second quarter of 2013, the Company's Board of Directors approved a stock compensation grant to eligible non-employee directors, which consisted of 129,680 shares.

The Company generally recognizes compensation expense for its stock-based awards ratably over the vesting period. Stock-based compensation expense for the three and six months ended June 30, 2013 and 2012 includes $0.9 million of expense related to stock awards granted to non-employee directors, which became fully vested on the grant date.

The following table summarizes the Company's unrecognized compensation expense and the weighted-average period over which the expense will be recognized as of June 30, 2013:

	June 30, 2013
	Unrecognized	Weighted Average
	Compensation	Years Expense To Be
(in millions of dollars, except weighted average years)	Expense	Recognized Over
Stock options	$6.2	2.3
RSUs	$8.9	2.1
PSUs	$12.3	1.9