Segment Information (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Revenue	$ 326,890	$ 288,670	$ 937,178	$ 841,805
Other Segments
Segment Reporting Information [Line Items]
Revenue	25,042	17,518	63,486	47,238
United States
Segment Reporting Information [Line Items]
Revenue	263,796	237,260	765,699	694,670
Canada
Segment Reporting Information [Line Items]
Revenue	$ 38,052	$ 33,892	$ 107,993	$ 99,897