Divestitures & Assets Held for Sale (Details) - USD ($)				12 Months Ended			24 Months Ended
	Oct. 01, 2020	Jan. 01, 2020	Oct. 01, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2021	Jan. 02, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax gain on sale of business				$ 6,064,000	$ 12,126,000	$ 0
Goodwill				35,939,000
Tuition Program Management Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price			$ 20,000,000.0
Consideration held in escrow			1,500,000
Additional consideration paid			100,000
Pre-tax gain on sale of business			12,100,000
Direct selling costs			100,000
Goodwill			$ 7,700,000
Alternative Fuels Division
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price		$ 4,800,000						$ 3,500,000
Pre-tax gain on sale of business		1,100,000
Goodwill				2,600,000
Advance payment					$ 1,500,000
Alternative Fuels Division | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax gain on sale of business		1,100,000
Direct selling costs		1,300,000
Disposal Group, Cash Payment for Settlement of Net Working Capital		$ 200,000
IC Axon [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax gain on sale of business	$ 5.0
IC Axon [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price	28,000,000.0
Pre-tax gain on sale of business	5,000,000.0
Direct selling costs	300,000
Goodwill	14,200,000
Accounts receivable	2,800,000
Escrow Deposit	1,500,000
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities	1,900,000
Disposal Group, Including Discontinued Operation, Intangible Assets	$ 7,000,000.0
EtaPRO | Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill				35,900,000
Deferred revenue				5,100,000
Disposal Group, Including Discontinued Operation, Accounts Payable				700,000
Disposal Group, Including Discontinued Operation, Unbilled Contracts Receivable				2,900,000
Disposal Group, Including Discontinued Operation, Accounts Receivable				$ 3,400,000
Subsequent Event | Alternative Fuels Division
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price subject to achievement milestones							$ 500,000