Subsequent Event - Applicable rates of credit agreement (Details) - Subsequent Event	1 Months Ended
	Apr. 30, 2021
if the First Lien Net Leverage Ratio is greater than or equal to 3.50:1.00
Subsequent Event [Line Items]
Commitment fee (as a percent)	0.30%
if the First Lien Net Leverage Ratio is less 3.50:1.00 but greater than or equal to 2.25:1.00
Subsequent Event [Line Items]
Commitment fee (as a percent)	0.25%
if the First Lien Net Leverage Ratio is less than 2.25:1.00
Subsequent Event [Line Items]
Commitment fee (as a percent)	0.20%
2021 Credit Agreement | if the First Lien Net Leverage Ratio is greater than or equal to 3.50:1.00 | Minimum
Subsequent Event [Line Items]
Net Leverage Ratio	1.00
2021 Credit Agreement | if the First Lien Net Leverage Ratio is greater than or equal to 3.50:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	3.50
2021 Credit Agreement | if the First Lien Net Leverage Ratio is less 3.50:1.00 but greater than or equal to 2.25:1.00 | Minimum
Subsequent Event [Line Items]
Net Leverage Ratio	1.00
2021 Credit Agreement | if the First Lien Net Leverage Ratio is less 3.50:1.00 but greater than or equal to 2.25:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	3.50
2021 Credit Agreement | if the First Lien Net Leverage Ratio is less than 2.25:1.00 | Minimum
Subsequent Event [Line Items]
Net Leverage Ratio	1.00
2021 Credit Agreement | if the First Lien Net Leverage Ratio is less than 2.25:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	2.25
2021 Credit Agreement | Federal funds effective rate
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	0.50%
2021 Credit Agreement | Federal funds effective rate | if the First Lien Net Leverage Ratio is less 3.50:1.00 but greater than or equal to 2.25:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	2.25
2021 Credit Agreement | one-month LIBOR
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	1.00%
2021 Credit Agreement | one-month LIBOR | if the First Lien Net Leverage Ratio is greater than or equal to 3.50:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	2.00%
2021 Credit Agreement | one-month LIBOR | if the First Lien Net Leverage Ratio is less 3.50:1.00 but greater than or equal to 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	1.75%
2021 Credit Agreement | one-month LIBOR | if the First Lien Net Leverage Ratio is less than 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	1.50%
2021 Credit Agreement | Base rate loans | if the First Lien Net Leverage Ratio is greater than or equal to 3.50:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	1.00%
2021 Credit Agreement | Base rate loans | if the First Lien Net Leverage Ratio is less 3.50:1.00 but greater than or equal to 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	0.75%
2021 Credit Agreement | Base rate loans | if the First Lien Net Leverage Ratio is less than 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	0.50%
2017 Credit Agreement | if the First Lien Net Leverage Ratio is greater than or equal to 3.00:1.00 | Minimum
Subsequent Event [Line Items]
Net Leverage Ratio	1.00
2017 Credit Agreement | if the First Lien Net Leverage Ratio is greater than or equal to 3.00:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	3.00
2017 Credit Agreement | if the First Lien Net Leverage Ratio is less 3.00:1.00 but greater than or equal to 2.25:1.00 | Minimum
Subsequent Event [Line Items]
Net Leverage Ratio	1.00
2017 Credit Agreement | if the First Lien Net Leverage Ratio is less 3.00:1.00 but greater than or equal to 2.25:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	3.00
2017 Credit Agreement | if the First Lien Net Leverage Ratio is less than 2.25:1.00 | Minimum
Subsequent Event [Line Items]
Net Leverage Ratio	1.00
2017 Credit Agreement | if the First Lien Net Leverage Ratio is less than 2.25:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	2.25
2017 Credit Agreement | Federal funds effective rate | if the First Lien Net Leverage Ratio is less 3.00:1.00 but greater than or equal to 2.25:1.00 | Maximum
Subsequent Event [Line Items]
Net Leverage Ratio	2.25
2017 Credit Agreement | one-month LIBOR | if the First Lien Net Leverage Ratio is greater than or equal to 3.00:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	2.00%
2017 Credit Agreement | one-month LIBOR | if the First Lien Net Leverage Ratio is less 3.00:1.00 but greater than or equal to 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	1.75%
2017 Credit Agreement | one-month LIBOR | if the First Lien Net Leverage Ratio is less than 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	1.50%
2017 Credit Agreement | Base rate loans | if the First Lien Net Leverage Ratio is greater than or equal to 3.00:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	1.00%
2017 Credit Agreement | Base rate loans | if the First Lien Net Leverage Ratio is less 3.00:1.00 but greater than or equal to 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	0.75%
2017 Credit Agreement | Base rate loans | if the First Lien Net Leverage Ratio is less than 2.25:1.00
Subsequent Event [Line Items]
Spread on variable rate (as a percent)	0.50%