Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Nonvested Restricted Stock Units and Changes During the Period

Nonvested restricted stock units as of June 30, 2023, and changes during the six months ended June 30, 2023 (unaudited) were as follows:

	Shares			Weighted Average Grant-Date Fair Value
Nonvested as of December 31, 2022		338,448		$	33.28
Granted		126,931			34.57
Vested		(8,426	)		35.95
Nonvested as of June 30, 2023		456,953		$	33.62

Schedule of Stock-Based Compensation Expense

The Company's stock-based compensation expense related to the restricted stock units during the three and six months ended June 30, 2023 and 2022 (unaudited), which was included in General and administrative expenses within the Condensed Consolidated Statements of Income, was as follows:

	Three Months Ended				Six Months Ended
(millions)	June 30, 2023		June 30, 2022		June 30, 2023		June 30, 2022
Stock-based compensation expense	$	1.4	$	1.5	$	2.5	$	2.8

The Company's stock-based compensation expense related to PSUs during the three and six months ended June 30, 2023 and 2022 (unaudited), which was included in General and administrative expenses within the Condensed Consolidated Statements of Income, was as follows:

	Three Months Ended				Six Months Ended
(millions)	June 30, 2023		June 30, 2022		June 30, 2023		June 30, 2022
Stock-based compensation expense	$	1.2	$	0.7	$	2.3	$	1.2

Summary of Nonvested PSU's and Changes During the Period

Nonvested PSUs as of June 30, 2023, and changes during the six months ended June 30, 2023 (unaudited), were as follows:

	Shares		Weighted Average Grant-Date Fair Value
Nonvested as of December 31, 2022		177,605	$	31.94
Granted		126,921		34.57
Nonvested as of June 30, 2023		304,526	$	33.04