Equity Investments (Investments and commitments) (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Transportation Resource Partners III [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	4.90%	[1],[2]
Total TRP investment commitment	$ 245,000
Amounts Committed To Invest	15,000
Remaining Investment Commitment	$ 0
Transportation Resource Partners IV [Member]
Schedule of Equity Method Investments [Line Items]
TRP ownership interest	4.20%	[1],[3],[4]
Total TRP investment commitment	$ 116,065
Amounts Committed To Invest	4,900
Remaining Investment Commitment	612
TRP Investment Commitment, Due in Next Twelve Months	100
TRP Investment Commitment, Due in Second and Third Year	500
TRP Investment Commitment, Due in Fourth and Fifth Year	0
TRP Investment Commitment, Due after Fifth Year	$ 0
Transportation Resource Partners, Colnvest Partners, (NTI) [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	0.00%	[1],[2],[5]
Total TRP investment commitment	$ 120,000
Amounts Committed To Invest	10,000
Remaining Investment Commitment	$ 0
Transportation Resource Partners, CoInvest Partners, (QLS) [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	25.00%	[1],[2]
Total TRP investment commitment	$ 39,000
Amounts Committed To Invest	9,735
Remaining Investment Commitment	$ 0
Transportation Resource Partners, CoInvest Partners, FFR I [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	7.40%	[1],[2]
Total TRP investment commitment	$ 66,555
Amounts Committed To Invest	4,950
Remaining Investment Commitment	$ 0
Transportation Resource Partners V
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	16.60%	[1],[2],[6]
Total TRP investment commitment	$ 180,700
Amounts Committed To Invest	30,000
Remaining Investment Commitment	10,814
TRP Investment Commitment, Due in Next Twelve Months	5,600
TRP Investment Commitment, Due in Second and Third Year	2,100
TRP Investment Commitment, Due in Fourth and Fifth Year	800
TRP Investment Commitment, Due after Fifth Year	$ 2,300
Transportation Resource Partners, Coinvest Partners, V (PW)
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	13.30%	[1],[2]
Total TRP investment commitment	$ 30,000
Amounts Committed To Invest	4,000
Remaining Investment Commitment	$ 0

[1] The Company's share of the results is included within "Other (expenses) income, net" in the consolidated statements of comprehensive income.

[2] The TRP III, TRP IV Coinvestments, TRP V, and TRP V Coinvest are unconsolidated majority interests. Management considered the criteria set forth in ASC 323, Investments – Equity Method and Joint Ventures, to establish the appropriate accounting treatment for these investments. This guidance requires the use of the equity method for recording investments in limited partnerships where the "so minor" interest is not met. As such, the investments are being accounted for under the equity method. Knight's ownership interest reflects its ultimate ownership of the portfolio companies underlying the TRP III, TRP IV Coinvestment NTI, TRP IV Coninvestment QLS, TRP IV Coinvestment FFR, TRP V, and TRP V Coninvest legal entities.

[3] In accordance with ASC 321, Investments – Equity Securities, these investments are recorded at cost minus impairment.

[4] Management anticipates that the following amounts will be due: $0.1 million in 2023, $0.5 million from 2024 through 2025, and none thereafter

[5] TRP IV Coinvestment NTI was liquidated during 2022.

[6] Management anticipates that the following amounts will be due: $5.6 million in 2023, $2.1 million from 2024 through 2025, $0.8 million from 2026 through 2027, and $2.3 million thereafter.