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Fair Value Measurements - Narrative (Details) - USD ($)	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019	Jul. 23, 2018	Dec. 09, 2011	Dec. 06, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers of assets between Level 1 and Level 2	$ 0		$ 0
Transfers of assets between Level 2 and Level 1	0		0
Transfers of liabilities between Level 1 and Level 2	0		0
Transfers of liabilities between Level 2 and Level 1	0		0
Contingent consideration			3,375,000
FLI
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent consideration		$ 3,000,000.0		$ 3,400,000
Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of our revolving facility and senior debt	1,127,600,000		876,000,000.0
Reported Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of our revolving facility and senior debt	$ 1,049,300,000		$ 850,200,000
3.00% Senior Notes, due May 2030
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	3.00%
3.20% Senior Notes, due June 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	3.20%		3.20%
3.37% Senior Notes, due June 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	3.37%		3.37%
4.50% Senior Notes, due December 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate			4.50%			4.50%
4.20% Senior Notes, due December 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	4.20%		4.20%		4.20%