Intangible Asset and Goodwill (Details 3) (USD $)	3 Months Ended		6 Months Ended					6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended			6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 Existing technology	Dec. 31, 2013 Existing technology	Jun. 30, 2014 Existing technology Minimum	Dec. 31, 2013 Existing technology Minimum	Jun. 30, 2014 Existing technology Maximum	Dec. 31, 2013 Existing technology Maximum	Jun. 30, 2014 Customer contracts and contractual relationships	Dec. 31, 2013 Customer contracts and contractual relationships	Jun. 30, 2014 Customer contracts and contractual relationships Minimum	Dec. 31, 2013 Customer contracts and contractual relationships Minimum	Jun. 30, 2014 Customer contracts and contractual relationships Maximum	Dec. 31, 2013 Customer contracts and contractual relationships Maximum	Jun. 30, 2014 Non-compete agreements	Dec. 31, 2013 Non-compete agreements	Jun. 30, 2014 Favorable contracts	Jun. 30, 2014 Favorable contracts	Jun. 30, 2013 Favorable contracts	Dec. 31, 2013 Favorable contracts
Components of intangible assets
Useful Life (in years)								3 years	3 years	10 years	10 years			1 year	1 year	10 years	10 years	3 years	3 years
Gross Carrying Amount	$ 216,714,000		$ 216,714,000		$ 217,595,000	$ 185,321,000	$ 186,202,000					$ 31,093,000	$ 31,093,000					$ 300,000	$ 300,000
Accumulated Amortization	(114,279,000)		(114,279,000)		(100,423,000)	(92,598,000)	(80,961,000)					(21,381,000)	(19,204,000)					(300,000)	(258,000)
Net Carrying Amount	102,435,000		102,435,000		117,172,000	92,723,000	105,241,000					9,712,000	11,889,000					0	42,000	100,000	100,000		1,000,000
Total Proceeds From Sale Of Intangible Assets			4,400,000
Cash received related to favorable contracts																				100,000	900,000	1,400,000
Amortization expense for intangible assets	$ 6,800,000	$ 7,000,000	$ 13,554,000	$ 14,037,000