Acquisition - Narrative (Details) customer in Thousands, $ in Thousands		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Aug. 31, 2020 USD ($) customer sale_representative	May 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Payments for purchase					$ 33,000	$ 0
Accrued acquisition liability			$ 0		0			$ 32,673
Interest expense			268	$ 72	591	187
Goodwill			35,674	$ 20,150	35,674	20,150	$ 20,923	35,176
Partsmaster
Business Acquisition [Line Items]
Number of customers | customer	16
Number of sales representatives | sale_representative	200
Purchase price	$ 35,300
Payments for purchase	2,300	$ 33,000
Accrued acquisition liability								$ 32,700
Interest expense			100		300
Goodwill	15,816
Revenue			15,300		31,000
Operating income since acquisition			$ 500		$ 1,100
Pro Forma revenue						91,100	197,300
Pro Forma net income						$ 1,400	$ 14,300
Partsmaster | Customer relationships
Business Acquisition [Line Items]
Intangibles	$ 4,961
Intangibles weighted average life	10 years
Partsmaster | Trade names
Business Acquisition [Line Items]
Intangibles	$ 2,775
Intangibles weighted average life	5 years