Acquisitions, Dispositions, and Deconsolidations - Schedule of Purchase Price Allocations, Bank Steel Acquisition (Details) - USD ($)	May 27, 2021	Sep. 30, 2021	Dec. 31, 2020
Purchase Consideration at Fair Value
Goodwill		$ 122,800,000	$ 111,000,000.0
Banker Steel Acquisition
Purchase Consideration at Fair Value
Bankers Steel debt - assumed	$ 6,300,000
Cash	25,000,000.0
Gross consideration	145,000,000.0
Less: Seller transaction costs - assumed	400,000
Less: Bankers debt - assumed	6,300,000
Less: R&W premium paid by seller	500,000
Consideration transferred	137,800,000
Cash and cash equivalents	9,300,000
Accounts receivable, net	111,300,000
Contract assets	1,900,000
Assets held for sale	700,000
Inventory	5,700,000
Other current assets	1,600,000
Property, plant, and equipment, net	58,600,000
Other assets	40,200,000
Intangibles, net	61,400,000
Goodwill	12,100,000
Total assets to be acquired	302,800,000
Accounts Payable	39,100,000
Contract liabilities	55,000,000.0
Other current liabilities	30,300,000
Other liabilities	34,200,000
Long-term debt, less current portion	6,400,000
Total liabilities to be assumed	165,000,000.0
Total net assets acquired	137,800,000
Banker Steel Acquisition | Sellers' Notes
Purchase Consideration at Fair Value
Face amount	49,600,000
Banker Steel Acquisition | Term Loan
Purchase Consideration at Fair Value
Face amount	110,000,000
Banker Steel Acquisition | Revolving Credit Facility
Purchase Consideration at Fair Value
Face amount	$ 64,100,000