Intangible Assets and Goodwill (Tables)

12 Months Ended

Dec. 31, 2017

Finite-Lived Intangible Assets [Line Items]

Schedule of Goodwill [Table Text Block]

	(in thousands)
Balance at December 31, 2016	$	100,212
Acquisition	32,198
Balance at December 31, 2017	$	132,410

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	2017
	Amortization period (years)	Gross Amount		Accumulated Amortization		Net intangible assets
		(in thousands)
Customer relationships	20	$	13,600	$	1,645	$	11,955
Tradename	0.5-6	8,100		5,769		2,331
Covenants not to compete	1-10	4,200		1,464		2,736
		$	25,900	$	8,878	$	17,022

	2016
	Amortization period (years)	Gross Amount		Accumulated Amortization		Net intangible assets
		(in thousands)
Customer relationships	20	$	7,600	$	1,187	$	6,413
Tradename	6	7,400		3,854		3,546
Covenants not to compete	10	3,100		969		2,131
		$	18,100	$	6,010	$	12,090