Fixed Assets Depreciation Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 16,409	$ 11,067	$ 31,686	$ 21,558