Impairments Impairments Fair Value Nonrecurring (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Long-lived assets held for use
Property, Plant and Equipment [Line Items]
Assets, fair value	$ 311,886	$ 65,203	$ 93,945
Long-lived assets held for use | Level 1
Property, Plant and Equipment [Line Items]
Assets, fair value	0	0	0
Long-lived assets held for use | Level 2
Property, Plant and Equipment [Line Items]
Assets, fair value	0	0	0
Long-lived assets held for use | Level 3
Property, Plant and Equipment [Line Items]
Assets, fair value	$ 311,886	65,203	$ 93,945
Long-lived assets sold during the year
Property, Plant and Equipment [Line Items]
Assets, fair value		70,733
Long-lived assets sold during the year | Level 1
Property, Plant and Equipment [Line Items]
Assets, fair value		0
Long-lived assets sold during the year | Level 2
Property, Plant and Equipment [Line Items]
Assets, fair value		0
Long-lived assets sold during the year | Level 3
Property, Plant and Equipment [Line Items]
Assets, fair value		$ 70,733