Goodwill and Intangibles (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of Change in Carrying Amount of Goodwill

The change in carrying amount of goodwill was as follows (in thousands):


	Goodwill (Gross)			Accumulated Impairment Losses			Goodwill (Net)
January 1, 2016	$	160,516		$	(70,004	)	$	90,512
Business combinations		16,918			—			16,918
Other		(344	)		—			(344	)

December 31, 2016		177,090			(70,004	)		107,086
Business combinations		47,727			—			47,727
Other		653			—			653

December 31, 2017	$	225,470		$	(70,004	)	$	155,466

Schedule of Gross Carrying Amount, Accumulated Amortization and Net Book Value

The following table provides the gross carrying amount, accumulated amortization and net book value for each major class of intangibles (in thousands):


	As of December 31,
	2017						2016
	Gross Carrying Amount		Accumulated Amortization		Net Book Value		Gross Carrying Amount		Accumulated Amortization		Net Book Value
Amortized intangibles:
Customer relationships	$	121,015	$	38,651	$	82,364	$	80,909	$	27,533	$	53,376
Covenants not-to-compete		11,807		4,773		7,034		8,602		2,466		6,136
Trademarks and tradenames		58,136		14,076		44,060		37,303		10,498		26,805
Backlog		13,600		9,067		4,533		—		—		—

	$	204,558	$	66,567	$	137,991	$	126,814	$	40,497	$	86,317

Schedule of Estimated Aggregate Annual Amortization

Remaining estimated aggregate annual amortization expense is as follows (in thousands):


2018	$	23,516
2019		18,387
2020		17,671
2021		16,653
2022		15,735
Thereafter		46,029