Fair Value Measurement - Available-For-Sale Investments Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities and Liabilities that are Measured at Fair Value [Line Items]
Estimated Fair Value	$ 998,859	$ 684,042
Time deposits [Member]
Schedule of Available-for-sale Securities and Liabilities that are Measured at Fair Value [Line Items]
Estimated Fair Value	805,603	345,780
Fair Value, Measurements, Recurring [Member] | Time deposits [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Schedule of Available-for-sale Securities and Liabilities that are Measured at Fair Value [Line Items]
Estimated Fair Value	805,603	345,780
Fair Value, Measurements, Recurring [Member] | Time deposits [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Available-for-sale Securities and Liabilities that are Measured at Fair Value [Line Items]
Estimated Fair Value	$ 805,603	$ 345,780