Business Segment Information - Summary of selected information between United States and all international locations (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 2,337,413	$ 1,861,489	$ 1,945,023
United States Revenues
Segment Reporting Information [Line Items]
Revenues	2,249,260	1,795,592	1,870,815
International Revenues
Segment Reporting Information [Line Items]
Revenues	$ 88,153	$ 65,897	$ 74,208