Related Party Transactions and Parent Company Equity - Schedule of Transfers To/From Parent (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Related Party Transaction [Line Items]      
Total net transfers (to)/from parent $ (6,371) $ (94,924) $ (113,753)
Cash pooling and general financing activities      
Related Party Transaction [Line Items]      
Total net transfers (to)/from parent (33,565) (182,184) (181,780)
Corporate allocations including income taxes      
Related Party Transaction [Line Items]      
Total net transfers (to)/from parent $ 27,194 $ 87,260 $ 68,027