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Stock-Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Schedule of Stock-based Compensation Plans
The table below summarizes certain data for our stock-based compensation plans (in millions):
Fiscal Year Ended December 31, 2025
Fiscal Year Ended December 31, 2024
Fiscal Year Ended December 31, 2023
Stock-based compensation expense - Profits Interests$— $2.9 $13.3 
Stock-based compensation expense - Omnibus Plan (excluding directors)$14.1 $11.5 $7.6 
Stock-based compensation expense - Omnibus Plan (directors)$1.0 $0.9 $0.7 
Tax benefit for stock-based compensation (1)
$1.9 $2.0 $2.4 
(1) Tax benefit (expense) was zero related to Profits Interests expense for the years ended December 31, 2025, 2024, and 2023.
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions The fair value of the PSUs is determined using a Monte Carlo simulation model on the grant date with the following assumptions:
March 1, 2025
MIR Stock Price$15.53 
Expected volatility(1)
45.28 %
Risk-free interest rate(2)
3.99 %
Dividend yield0.00 %
Fair value$17.18 
(1) Expected volatility is based on historical volatilities from a group of comparable entities for a time period similar to that of the expected term.
(2) The risk-free rate is based on an average of U.S. Treasury yields in effect at the time of grant corresponding with the expected term.
The fair value of the PSUs is determined using a Monte Carlo simulation model on the grant date with the following assumptions:
March 1, 2024
MIR Stock Price$9.96 
Expected volatility(1)
43.69 %
Risk-free interest rate(2)
4.36 %
Dividend yield0.00 %
Fair value$9.97 
(1) Expected volatility is based on historical volatilities from a group of comparable entities for a time period similar to that of the expected term.
(2) The risk-free rate is based on an average of U.S. Treasury yields in effect at the time of grant corresponding with the expected term.
The fair value of the market condition PSUs is determined using a Monte Carlo simulation model on the grant date with the following assumptions:
March 29, 2023
MIR Stock Price$8.06 
Expected volatility(1)
45.30 %
Risk-free interest rate(2)
3.92 %
Dividend yield0.00 %
Fair value$11.83 
(1) Expected volatility is based on historical volatilities from a group of comparable entities for a time period similar to that of the expected term.
(2) The risk-free rate is based on an average of U.S. Treasury yields in effect at the time of grant corresponding with the expected term.
Schedule of Activity of RSUs, PSUs, and Director RSUs
Activity of our RSUs, PSUs, and Director RSUs is as follows:

RSUsPSUsDirector RSUs
QuantityWeighted average grant date fair valueQuantityWeighted average grant date fair valueQuantityWeighted average grant date fair value
Total awards outstanding at December 31, 20221,659,026 $9.05 411,406 $9.50 48,934 $6.68 
Awards granted729,829 8.05 322,323 9.42 82,950 7.89 
Awards vested500,603 9.06 — — 90,409 7.24 
Awards forfeited242,173 8.55 27,193 9.93 — — 
Total awards outstanding at December 31, 20231,646,079 $8.68 706,536 $9.45 41,475 $7.89 
Awards granted581,714 10.08 563,809 9.62 94,500 10.37 
Awards vested690,652 8.78 — — 88,725 9.21 
Awards forfeited87,087 8.93 12,048 9.97 — — 
Total awards outstanding at December 31, 20241,450,054 $9.18 1,258,297 $9.52 47,250 $10.37 
Awards granted446,382 19.01 710,450 16.77 55,839 17.55 
Awards vested836,719 9.10 555,859 6.96 75,166 13.04 
Awards forfeited44,690 17.98 31,850 10.81 — — 
Total awards outstanding at December 31, 20251,015,027 $13.48 1,381,038 $11.86 27,923 $17.55 
Schedule of Unrecognized Compensation Cost
Unrecognized compensation cost and weighted average periods remaining for non-vested awards as of December 31, 2025, are as follows (dollars in millions):

As of December 31, 2025
Weighted average period remaining for non-vested awards as of December 31, 2025
RSUs$9.5 1.7 years
PSUs9.3 1.8 years
Director RSUs0.4 3 months
Total unrecognized compensation cost$19.2