Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Intangible assets
Amortization expense of intangible assets	$ 1,891	$ 1,476	$ 5,576	$ 4,669
Estimated future amortization expense for intangible assets
2013 (remaining three months)	1,891		1,891
2014	7,454		7,454
2015	6,404		6,404
2016	6,029		6,029
2017	5,909		5,909
Thereafter	20,315		20,315
Total	48,002		48,002		51,978
Tradename
Estimated future amortization expense for intangible assets
Total	21,808		21,808		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	2,991		2,991		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	23,203		23,203		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