Identified Intangible Assets and Goodwill, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquired finite-lived intangible assets [line Items]
Finite-lived intangible assets, gross	$ 40,170	$ 34,798
Accumulated amortization	30,640	28,604
Intangible assets, net	9,530	6,194
Goodwill	37,971	35,477	$ 30,305
Identified intangible assets and goodwill, net	$ 47,501	41,671
Customer lists/relationships
Acquired finite-lived intangible assets [line Items]
Finite-lived intangible assets, remaining amortization period	3 years 7 months 6 days
Finite-lived intangible assets, gross	$ 25,179	21,487
Accumulated amortization	$ 18,251	16,846
Employment-related
Acquired finite-lived intangible assets [line Items]
Finite-lived intangible assets, remaining amortization period	2 years 9 months 18 days
Finite-lived intangible assets, gross	$ 8,133	7,333
Accumulated amortization	$ 6,954	6,624
Tradenames
Acquired finite-lived intangible assets [line Items]
Finite-lived intangible assets, remaining amortization period	3 years 8 months 12 days
Finite-lived intangible assets, gross	$ 6,858	5,978
Accumulated amortization	$ 5,435	$ 5,134