Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Intangible assets
Amortization expense of intangible assets	$ 1,891	$ 1,447	$ 3,685	$ 3,193
Estimated future amortization expense for intangible assets
2013 (remaining six months)	3,655		3,655
2014	7,489		7,489
2015	7,220		7,220
2016	6,274		6,274
2017	5,909		5,909
Thereafter	19,346		19,346
Total	49,893		49,893		51,978
Tradename
Estimated future amortization expense for intangible assets
Total	22,593		22,593		23,586
Tradename | Minimum
Intangible assets
Amortization Period			3 years
Tradename | Maximum
Intangible assets
Amortization Period			10 years
Non-compete agreements
Estimated future amortization expense for intangible assets
Total	3,407		3,407		4,130
Non-compete agreements | Minimum
Intangible assets
Amortization Period			2 years
Non-compete agreements | Maximum
Intangible assets
Amortization Period			5 years
Customer relationship
Estimated future amortization expense for intangible assets
Total	23,893		23,893		24,212
Customer relationship | Minimum
Intangible assets
Amortization Period			5 years
Customer relationship | Maximum
Intangible assets
Amortization Period			15 years
Backlog
Intangible assets
Amortization Period			9 months
Estimated future amortization expense for intangible assets
Total					$ 50