Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Aug. 05, 2015	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense		$ 7,287	$ 4,418
TAS Commercial Concrete
Finite-Lived Intangible Assets [Line Items]
Amortization expense		$ 7,300
TAS Commercial Concrete | Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles acquired	$ 18,100
Acquired finite-lived intangible assets, useful life	8 years
TAS Commercial Concrete | Contractual backlog
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangibles acquired	$ 8,700
Acquired finite-lived intangible assets, useful life	2 years
Reported Value Measurement [Member] | TAS Commercial Concrete | Trade Names
Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure	$ 6,900