Stock-Based Compensation - Summary of Restricted Stock Unit and PSU Activity (Detail)	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Time-Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Unvested shares of restricted stock and restricted stock units outstanding at beginning of period | shares	369,600
Restricted Stock Awards and restricted stock units, Granted | shares	362,200
Restricted Stock Awards and restricted stock units, Vested | shares	(218,400)
Restricted Stock Awards and restricted stock units, Forfeited | shares	(48,300)
Unvested shares of restricted stock and restricted stock units outstanding at end of period | shares	465,100
Unvested shares of restricted stock and restricted stock units outstanding, Weighted Average Grant Date Fair Value Per Share, at beginning of period | $ / shares	$ 259.94
Granted, Weighted Average Grant Date Fair Value Per Share | $ / shares	301.86
Vested, Weighted Average Grant Date Fair Value Per Share | $ / shares	201.26
Forfeited, Weighted Average Grant Date Fair Value Per Share | $ / shares	315.59
Unvested shares of restricted stock and restricted stock units outstanding, Weighted Average Grant Date Fair Value Per Share, at end of period | $ / shares	$ 314.37
Time-based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Restricted Stock Awards and restricted stock units, Granted | shares	500
Unvested shares of restricted stock and restricted stock units outstanding at end of period | shares	500	[1]
Granted, Weighted Average Grant Date Fair Value Per Share | $ / shares	$ 377.01
Unvested shares of restricted stock and restricted stock units outstanding, Weighted Average Grant Date Fair Value Per Share, at end of period | $ / shares	$ 377.01	[1]
Market-Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Unvested shares of restricted stock and restricted stock units outstanding at beginning of period | shares	1,628,300
Restricted Stock Awards and restricted stock units, Granted | shares	59,500
Restricted Stock Awards and restricted stock units, Vested | shares	(100)
Restricted Stock Awards and restricted stock units, Forfeited | shares	(8,100)
Unvested shares of restricted stock and restricted stock units outstanding at end of period | shares	1,679,600
Unvested shares of restricted stock and restricted stock units outstanding, Weighted Average Grant Date Fair Value Per Share, at beginning of period | $ / shares	$ 111.87
Granted, Weighted Average Grant Date Fair Value Per Share | $ / shares	269.00
Vested, Weighted Average Grant Date Fair Value Per Share | $ / shares	347.62
Forfeited, Weighted Average Grant Date Fair Value Per Share | $ / shares	280.23
Unvested shares of restricted stock and restricted stock units outstanding, Weighted Average Grant Date Fair Value Per Share, at end of period | $ / shares	$ 116.61
Performance-Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Unvested shares of restricted stock and restricted stock units outstanding at beginning of period | shares	37,100
Restricted Stock Awards and restricted stock units, Granted | shares	51,500
Restricted Stock Awards and restricted stock units, Forfeited | shares	(10,800)
Unvested shares of restricted stock and restricted stock units outstanding at end of period | shares	77,800	[1]
Unvested shares of restricted stock and restricted stock units outstanding, Weighted Average Grant Date Fair Value Per Share, at beginning of period | $ / shares	$ 556.50
Granted, Weighted Average Grant Date Fair Value Per Share | $ / shares	296.07
Forfeited, Weighted Average Grant Date Fair Value Per Share | $ / shares	376.69
Unvested shares of restricted stock and restricted stock units outstanding, Weighted Average Grant Date Fair Value Per Share, at end of period | $ / shares	$ 409.13	[1]

[1] A maximum of 194,478 shares could be delivered upon settlement of PSUs based upon Paycom’s Relative TSR over the applicable performance periods.