Summary of Significant Accounting Policies - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	$ 6,907	$ 5,898
Impact of new accounting standard	695
Bad debt expense (benefit)	5,253	2,978	$ 3,562
Deductions for uncollectible receivables written off, net of recoveries	(2,166)	(3,924)
Credit allowance of acquired companies on the acquisition date	335	1,955
Reclass to other current liabilities	(315)
Balance at end of year	10,709	6,907	$ 5,898
Service
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	3,192
Impact of new accounting standard	310
Bad debt expense (benefit)	2,566
Deductions for uncollectible receivables written off, net of recoveries	(1,431)
Balance at end of year	4,637	3,192
Construction
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	3,400
Impact of new accounting standard	331
Bad debt expense (benefit)	2,697
Deductions for uncollectible receivables written off, net of recoveries	(735)
Credit allowance of acquired companies on the acquisition date	335
Balance at end of year	6,028	3,400
Other.
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	315
Impact of new accounting standard	54
Bad debt expense (benefit)	(10)
Reclass to other current liabilities	(315)
Balance at end of year	$ 44	$ 315