Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income and Other Expenses (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Changes in accumulated other comprehensive items    
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance $ (75,031) $ (8,660)
Other comprehensive loss:    
Foreign currency translation adjustments (56,074) 1,677
Market value adjustments for securities 23  
Total Other comprehensive (loss) income (56,051) 1,677
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance (131,082) (6,983)
Other Expense (Income), Net:    
Foreign currency transaction losses (gains), net 22,266 6,438
Other, net 83 (1,121)
Other Expense, Net 22,349 5,317
Foreign currency translation adjustments    
Changes in accumulated other comprehensive items    
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance (76,010) (9,586)
Other comprehensive loss:    
Foreign currency translation adjustments (56,074) 1,677
Market value adjustments for securities 0  
Total Other comprehensive (loss) income (56,074) 1,677
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance (132,084) (7,909)
Market value adjustments for securities    
Changes in accumulated other comprehensive items    
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance 979 926
Other comprehensive loss:    
Foreign currency translation adjustments 0 0
Market value adjustments for securities 23  
Total Other comprehensive (loss) income 23 0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance $ 1,002 $ 926