Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2021

Incentive Plans

Market Performance Based Awards

			Market
	2019	2020 and 2021	Performance
	RMS Relative	RMS Relative	Vesting
Level	Market Performance	Market Performance	Percentage
Below Threshold Level	≤ -300 basis points	≤ -500 basis points	0	%
Threshold Level	-300 basis points	-500 basis points	25	%
Target Level	100 basis points	0 basis points	50	%
High Level	≥ 500 basis points	≥ 500 basis points	100	%

Schedule of Valuation Assumptions

	Expected Stock Price		Risk-Free Interest
Award Date	Volatility		Rate
January 1, 2019	23	%	2.44	%
February 21, 2019	23	%	2.48	%
February 19, 2020	22	%	1.39	%
February 20, 2020	22	%	1.35	%
January 1, 2021	27	%	0.17	%
February 25, 2021	26	%	0.31	%

Schedule of compensation expense and unearned compensation

Below is a summary of compensation expense and unearned compensation (in millions):

																	Expected
																	period to
	Deferred Compensation												Unearned Compensation				recognize
	Expensed						Capitalized						As of		As of		unearned
	Year Ended December 31,						Year Ended December 31,						December 31,		December 31,		compensation
Type of incentive award	2021		2020		2019		2021		2020		2019		2021		2020		(in years)
Long-term incentive units	$	15.4	$	12.8	$	8.7	$	0.2	$	0.2	$	0.2	$	19.8	$	15.1	2.5
Performance-based awards		23.9		24.8		13.0		0.7		0.6		0.8		39.2		34.4	1.1
Service-based restricted stock units		23.2		15.1		11.5		3.3		3.2		2.8		44.5		41.5	2.4
Interxion awards		17.7		19.7		—		—		—		—		8.5		27.2	1.8

Schedule of weighted average fair value

The following table sets forth the weighted-average fair value of for each type of incentive award at the date of grant for the years ended December 31, 2021, 2020 and 2019:

	Weighted Average Fair Value at Date of Grant
Type of incentive award	2021		2020		2019
Long-term incentive units	$	132.66	$	134.55	$	116.22
Performance-based awards		137.69		159.34		114.97
Restricted stock		129.52		138.82		115.25
Interxion awards		—		120.67		—

Summary of Long-Term Incentive Unit Activity

		Weighted-Average		Weighted-Average		Aggregate
		Grant Date Fair		Remaining Contractual		Intrinsic Value
Unvested Long-term Incentive Units	Units	Value		Life (Years)		(in thousands)
Unvested, beginning of period	235,535	$	122.22
Granted	151,093		139.08
Vested	(134,284)		121.63
Cancelled or expired	(1,876)		128.38
Unvested, end of period	250,468	$	132.66		1.97	$	44,300

(1) The intrinsic value is calculated based on the market value of our common stock as of December 31, 2021.

Summary of Restricted Stock Activity

		Weighted-Average		Weighted-Average			Aggregate
		Grant Date Fair		Remaining Contractual			Intrinsic Value (1)
Unvested Restricted Stock	Shares	Value		Life (Years)			(in thousands)
Unvested, beginning of period	783,219	$	123.04
Granted	265,576		137.30
Vested	(475,702)		123.17
Cancelled or expired	(63,724)		129.62
Unvested, end of period	509,369	$	129.52		2.20	$	90,092

(1) The intrinsic value is calculated based on the market value of our common stock as of December 31, 2021.