Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands, SEK in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2017 SEK	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 01, 2016 USD ($)
Finite-Lived Intangible Assets
Reserve for estimated returns, discounts and allowances	$ (42,000)		$ (38,000)
Reserve for uncollectible accounts	58,000		46,000
Depreciation	129,000		115,000	$ 94,000
Amortization expense	102,000		83,000	34,000
Estimated annual amortization expense in year one	97,000
Estimated annual amortization expense in year two	81,000
Estimated annual amortization expense in year three	65,000
Estimated annual amortization expense in year four	55,000
Estimated annual amortization expense in year five	48,000
Self-insurance reserve, total	94,000		84,000
Self-insurance reserve, current	$ 43,000		40,000
Percentage threshold to measure tax benefit	50.00%	50.00%
Equity method investments	$ 208,404		183,467	2,755
Investments in unconsolidated subsidiaries	7,664
Equity in earnings (loss) of unconsolidated subsidiaries	5,907		(592)	$ (6,104)
Self-insurance
Finite-Lived Intangible Assets
Outstanding letters of credit	71,000		$ 70,000
Raw Materials [Member]
Finite-Lived Intangible Assets
Manufactured Inventory	10,000
Aftermarket and refurbished products
Finite-Lived Intangible Assets
Inventories (3)	95,000
Salvage and remanufactured products
Finite-Lived Intangible Assets
Inventories (3)	$ 35,000
Salvage Mechanical Products
Finite-Lived Intangible Assets
Standard warranty period	6 months	6 months
Remanufactured Engines
Finite-Lived Intangible Assets
Standard warranty period	3 years	3 years
All 2016 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	16 years 6 months	16 years 6 months
Rhiag
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			16 years 2 months 12 days
Inventories (3)			$ 239,529
Intangible assets recognized			$ 429,360
PGW
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			11 years 4 months 24 days
Inventories (3)			$ 169,159
Intangible assets recognized			$ 37,954
All 2016 Acquisitions Excluding Rhiag and PGW [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			11 years 1 month 6 days
Inventories (3)			$ 62,223
Intangible assets recognized			$ 2,537
All 2015 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			15 years 9 months 18 days
Inventories (3)			$ 470,911
Intangible assets recognized			$ 469,851
Trade names and trademarks | Minimum
Finite-Lived Intangible Assets
Useful life, years	4 years	4 years
Trade names and trademarks | Maximum
Finite-Lived Intangible Assets
Useful life, years	30 years	30 years
Trade names and trademarks | All 2016 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	11 years 2 months 12 days	11 years 2 months 12 days
Trade names and trademarks | Rhiag
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			20 years
Trade names and trademarks | PGW
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			20 years
Trade names and trademarks | All 2016 Acquisitions Excluding Rhiag and PGW [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			20 years
Trade names and trademarks | All 2015 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			20 years
Software and technology related assets | Minimum
Finite-Lived Intangible Assets
Useful life, years	3 years	3 years
Software and technology related assets | Maximum
Finite-Lived Intangible Assets
Useful life, years	15 years	15 years
Software and technology related assets | All 2016 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	11 years 1 month 6 days	11 years 1 month 6 days
Software and technology related assets | Rhiag
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			5 years
Software and technology related assets | PGW
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			14 years 7 months 20 days
Software and technology related assets | All 2016 Acquisitions Excluding Rhiag and PGW [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			5 years 5 months 12 days
Software and technology related assets | All 2015 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			5 years 8 months 12 days
Covenants not to compete | Minimum
Finite-Lived Intangible Assets
Useful life, years	2 years	2 years
Covenants not to compete | Maximum
Finite-Lived Intangible Assets
Useful life, years	5 years	5 years
Covenants not to compete | All 2016 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	4 years 4 months 24 days	4 years 4 months 24 days
Covenants not to compete | PGW
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			5 years
Covenants not to compete | All 2016 Acquisitions Excluding Rhiag and PGW [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			2 years
Covenants not to compete | All 2015 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			4 years 9 months 28 days
Customer and supplier relationships [Member] | Minimum
Finite-Lived Intangible Assets
Useful life, years	6 years	6 years
Customer and supplier relationships [Member] | Maximum
Finite-Lived Intangible Assets
Useful life, years	20 years	20 years
Customer and supplier relationships [Member] | All 2016 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	18 years 7 months 6 days	18 years 7 months 6 days
Customer and supplier relationships [Member] | Rhiag
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			15 years
Customer and supplier relationships [Member] | PGW
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			10 years
Customer and supplier relationships [Member] | All 2015 Acquisitions [Member]
Finite-Lived Intangible Assets
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			14 years 5 months 29 days
Mekonomen [Member]
Finite-Lived Intangible Assets
Investment in unconsolidated subsidiary, ownership percentage	26.50%
Equity method investments	$ 202,000				$ 181,000
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	127,000
Equity in earnings (loss) of unconsolidated subsidiaries	7,000
Equity Method Investments, Fair Value Disclosure	173,000
Proceeds from Equity Method Investment, Dividends or Distributions	$ 7,000	SEK 67