Revenue from External Customers and Asset, by Geographical Areas (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	$ 1,987,008	$ 3,271,197	$ 3,018,175
Revenues	3,278,420	3,157,796	3,094,018
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	1,943,216	3,204,283	2,940,980
Revenues	3,209,736	3,075,387	3,035,558
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	38,898	59,841	69,826
Revenues	63,803	72,202	47,171
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	4,894	7,073	7,369
Revenues	$ 4,881	$ 10,207	$ 11,289