Acquisitions and Disposition of Business Line - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) business	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Goodwill	$ 80,642	$ 96,890	$ 96,916
Proceeds from sale of business	0	39,187	0
Pretax loss on disposition of business line	0	20,270	$ 0
Global Technical Services businesses
Business Acquisition [Line Items]
Business combinations, total consideration	2,431	3,400
Payments to acquire businesses, gross	1,519	2,500
Cash and cash equivalents acquired	135	134
Cash to be paid in one year	234	348
Cash to be paid in three years	351
Contingent consideration	327	377
Business combination, definite-lived intangible assets	951	1,094
Goodwill	$ 1,164	$ 1,296
Number of businesses acquired | business		2
Business combination, net tangible assets		$ 462
Business combination, deferred taxes		202
Garden City Group
Business Acquisition [Line Items]
Proceeds from sale of business		42,636
Disposal group, assets at time of sale		70,630
Disposal group, liabilities at time of sale		10,147
Pretax loss on disposition of business line		$ 20,270