Intangible Assets and Goodwill (Tables)

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

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

	2018
	Amortization period (years)	Gross Amount		Accumulated Amortization		Net intangible assets
		(in thousands)
Customer relationships	20	13,600		2,329		$	11,271
Tradename	0.5-6	8,100		7,021		1,079
Covenants not to compete	1-10	4,200		2,056		2,144
		$	25,900	$	11,406	$	14,494

	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

Schedule of Goodwill [Table Text Block]

Changes in carrying amount of goodwill during the twelve months ended December 31, 2018 and December 31, 2017 were as follows:

	(in thousands)
Balance at December 31, 2016	$	100,212
Acquisition	32,198
Balance at December 31, 2017	$	132,410
Acquisition	—
Balance at December 31, 2018	$	132,410