Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Jan. 29, 2021 USD ($) compensationPlan $ / shares shares	Jan. 31, 2020 USD ($) $ / shares shares	Feb. 01, 2019 USD ($) $ / shares	Jan. 14, 2019	Jan. 30, 2015 shares	Jun. 30, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated compensation cost	$ 2.0	$ 3.0	$ 14.0
Number of stock based compensation plans | compensationPlan	4
Document Period End Date	Jan. 29, 2021
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, net of estimated forfeitures	$ 2.0
Expected weighted-average period of recognition, years	1 year 1 month 6 days
Performance share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target shares	200.00%	150.00%
Unrecognized compensation cost, net of estimated forfeitures	$ 5.6
Expected weighted-average period of recognition, years	1 year 8 months 12 days
Awards granted (in dollars per share) | $ / shares	$ 74.40	$ 79.04	$ 85.31
Fair value of vesting awards that vested	$ 5.0
Below threshold level of performance (in shares) | shares	0	0
Percentage of awards presented for target number of shares	100.00%
Share awards granted upon future achievement (in shares) | shares	200,000
Vesting stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards assumed (in shares) | shares		642,000
Awards assumed (in dollars per share) | $ / shares		$ 65.03
Unrecognized compensation cost, net of estimated forfeitures	$ 39.0
Expected weighted-average period of recognition, years	1 year 3 months 18 days
Awards granted (in dollars per share) | $ / shares	$ 76.41	$ 76.01	$ 84.28
Fair value of vesting awards that vested	$ 32.0	$ 35.0	$ 60.0
Share-based Payment Arrangement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted, value, share-based compensation		42.0
Share-based Payment Arrangement, Pre-combination
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted, value, share-based compensation		22.0
Share-based Payment Arrangement, Post-combination
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted, value, share-based compensation		$ 20.0
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under plan (in shares) | shares					5,700,000	8,500,000
2013 Equity Incentive Plan | Employee Stock Option Granted Thereafter
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of stock awards vest or exercisable after one year	33.00%
Percentage of stock awards vest or exercisable after two years	33.00%
Percentage of stock awards vest or exercisable after three years	33.00%
2013 Equity Incentive Plan | Vesting Stock Awards Granted Thereafter
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of stock awards vest or exercisable after one year	25.00%
Percentage of stock awards vest or exercisable after two years	25.00%
Percentage of stock awards vest or exercisable after three years	25.00%
Percentage of stock awards vest or exercisable after four years	25.00%
2013 Equity Incentive Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term	7 years
2013 Equity Incentive Plan | Employee Stock Option | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term	10 years
2013 Equity Incentive Plan | Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under plan (in shares) | shares	3,400,000
Percentage of market price for employee purchase program for stock purchases during non-compensatory period	5.00%
Employee Stock Purchase Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of market price for employee purchase program for stock purchases during non-compensatory period	15.00%
Engility Holdings, Inc
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business combination, equity right conversion, common shares conversion ratio				0.45
Vesting after one year | 2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	33.00%
Vesting after two years | 2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	33.00%
Vesting after three years | 2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	33.00%