Debt Obligations - Other (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) item	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Debt Obligations
Payments on term loan	$ 7,500	$ 7,500
Outstanding balance	412,657		$ 388,220
Reconciliation of Credit Facility Adjusted EBITDA to net income
Net income	86,762	26,491
Provision for income taxes	(49,053)	8,737
Stock-based compensation	3,996	$ 4,711
Revolving credit facility
Debt Obligations
Borrowing capacity	450,000
Outstanding borrowings	260,000
Outstanding balance	260,000		220,000
Letters of credit amount outstanding	55,600
Credit available	$ 134,400
Principal financial covenants
Number of interest rate options | item	2
Other disclosures
Range of stated interest rates (as a percent)	1.90%
Revolving credit facility | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: Less than 1.00
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Letter of credit fees (as a percent)	1.25%
Commitment fees payable on unused portion of the facility (as a percent)	0.20%
Revolving credit facility | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: 2.50 or greater
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Letter of credit fees (as a percent)	2.00%
Commitment fees payable on unused portion of the facility (as a percent)	0.35%
Revolving credit facility | Base Rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: Less than 1.00
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	0.25%
Revolving credit facility | Base Rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: 1.00 to 1.75
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	0.50%
Revolving credit facility | Base Rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: 1.75 to 2.50
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	0.75%
Revolving credit facility | Base Rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: 2.50 or greater
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	1.00%
Revolving credit facility | Eurodollar rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: Less than 1.00
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	1.25%
Revolving credit facility | Eurodollar rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: 1.00 to 1.75
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	1.50%
Revolving credit facility | Eurodollar rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: 1.75 to 2.50
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	1.75%
Revolving credit facility | Eurodollar rate | Consolidated Total Indebtedness to Credit Facility Adjusted EBITDA: 2.50 or greater
Debt Instrument, Interest Rate, Effective Percentage [Abstract]
Additional per annum interest margin (as a percent)	2.00%
Amended senior revolving credit facility
Debt Obligations
Borrowing capacity	$ 562,500		600,000
Line of credit borrowing capacity accordion option	150,000
Payments on term loan	37,500
Term loan
Debt Obligations
Borrowing capacity	150,000
Outstanding balance	$ 112,500		120,000
Other disclosures
Range of stated interest rates (as a percent)	2.00%
Notes to Former Owners
Other disclosures
Cumulative number of companies acquired | item	9
Outstanding balance	$ 40,157		$ 47,954
Letter of Credit
Debt Obligations
Borrowing capacity	$ 160,000