Long-Lived Assets (Details) (USD $) In Thousands, unless otherwise specified					12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Computer equipment	Dec. 31, 2012 Computer equipment	Dec. 31, 2013 Computer equipment Minimum	Dec. 31, 2013 Computer equipment Maximum	Dec. 31, 2013 Leasehold improvements	Dec. 31, 2012 Leasehold improvements	Dec. 31, 2013 Leasehold improvements Minimum	Dec. 31, 2013 Leasehold improvements Maximum	Dec. 31, 2013 Operating equipment	Dec. 31, 2012 Operating equipment	Dec. 31, 2013 Operating equipment Minimum	Dec. 31, 2013 Operating equipment Maximum	Dec. 31, 2013 Furniture and equipment	Dec. 31, 2012 Furniture and equipment	Dec. 31, 2013 Furniture and equipment Minimum	Dec. 31, 2013 Furniture and equipment Maximum	Dec. 31, 2013 Capital projects in process	Dec. 31, 2012 Capital projects in process
Summary of Property and Equipment
Property and equipment, gross	$ 164,583	$ 160,072	$ 89,605	$ 76,924			$ 15,793	$ 14,415			$ 48,759	$ 58,684			$ 10,426	$ 9,990				$ 59
Less—accumulated depreciation	(129,522)	(120,643)
Property and equipment, net	$ 35,061	$ 39,429
Property and equipment, useful lives					3 years	5 years			5 years	10 years			3 years	5 years			3 years	8 years