Equity Incentive Plan (Tables)

12 Months Ended

Dec. 31, 2021

Equity Incentive Plan

Schedule of restricted share activity

Restricted share activity is summarized as follows:

	Shares	Weighted Average
	Outstanding	Grant Date
	(in thousands)	Fair Value
Unvested restricted stock at December 31, 2018	212	$	42.74
Restricted stock granted	54	$	65.85
Restricted stock vested	(70)	$	39.55
Restricted stock forfeited	(2)	$	54.08
Unvested restricted stock at December 31, 2019	194	$	50.71
Restricted stock granted	52	$	78.43
Restricted stock vested	(68)	$	45.78
Restricted stock forfeited	(3)	$	63.80
Unvested restricted stock at December 31, 2020	175	$	60.53
Restricted stock granted	87	$	65.23
Restricted stock vested	(64)	$	53.82
Restricted stock forfeited	(23)	$	63.88
Unvested restricted stock at December 31, 2021	175	$	64.90

Schedule of valuation assumptions used

During the years ended December 31, 2021, 2020 and 2019 the following assumptions were used:

Year Ended December 31,	2021		2020		2019
Expected term (years)	2.9		2.9		2.9
Volatility	33.9	%	18.4	%	19.7	%
Risk-free rate	0.2	%	1.3	%	2.5	%

Schedule of performance share and unit activity

Performance share and unit activity is summarized as follows:

	Target Number	Weighted Average
	of Awards	Grant Date
	(in thousands)	Fair Value
Performance shares at December 31, 2018	31	$	55.29
Performance units granted	30	$	66.96
Performance units and shares at December 31, 2019	61	$	61.04
Performance units granted	26	$	90.17
Performance units and shares at December 31, 2020	87	$	69.61
Performance units granted	43	$	63.42
Performance units and shares at December 31, 2021 - three-year performance period completed	(31)	$	55.29
Performance units and shares forfeited	(21)	$	68.79
Performance units and shares at December 31, 2021 - three-year performance period to be completed	78	$	63.35

	Shares	Weighted Average
	Outstanding	Grant Date
	(in thousands)	Fair Value
Performance shares - three-year performance period completed but not yet vested at December 31, 2020	—	$	—
Shares earned at completion of three-year performance period (1)	47	$	55.29
Shares vested	(16)	$	55.29
Shares forfeited	(4)	$	55.29
Performance shares - three-year performance period completed but not yet vested December 31, 2021	27	$	55.29
(1)Performance shares granted in 2018 for which the three-year performance period was completed in 2021 paid out at the 150% maximum performance level