Convertible Senior Notes - Narrative (Details)		12 Months Ended
	Nov. 12, 2014 USD ($) d $ / shares shares	Dec. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes, net | $		$ 0	$ 1,305,414,000	$ 0
Price per share of stock sold (in dollars per share) | $ / shares		$ 225.08
Payments for convertible note hedges | $		$ 0	247,969,000	0
Proceeds from issuance of warrants | $	$ 167,300,000	$ 0	$ 167,296,000	$ 0
Warrants sold, shares authorized to sell to counterparties | shares	4,490,020
Warrants sold, exercise price of shares authorized to sell to counterparties (in dollars per share) | $ / shares	$ 381.82
Convertible Debt [Member]
Debt Instrument [Line Items]
Note payable | $	$ 1,322,500,000.000000
Proceeds from issuance of convertible senior notes, net | $	$ 1,305,300,000
Interest rate	0.50%
Conversion ratio	0.0033951
Conversion price per share (in dollars per share) | $ / shares	$ 294.54
Convertible Notes, threshold trading days | d	20
Convertible Notes, threshold consecutive trading days	30 days
Convertible Notes per $1,000 principle, threshold business days | d	5
Convertible Notes per $1,000 principle, threshold consecutive trading days	5 days
Transaction costs related to issuance of Notes | $	$ 700,000
Warrants sold, exercise price of shares authorized to sell to counterparties (in dollars per share) | $ / shares	$ 381.82
Cumulative dilutive effect when price of stock exceeds conversion price, additional dilution at declining rate, cumulative shares effect (in shares) | shares	1,229,000
Cumulative dilutive effect when price of stock exceeds conversion price, additional dilution at declining rate after hedging activity, actual shares diluted (in shares) | shares	115,000
Cumulative dilutive effect when price of stock exceeds conversion price, additional dilution at declining rate after hedging activity, actual diluted share price (in dollars per share) | $ / shares	$ 391.82
Class A Common Stock [Member] | Convertible Debt [Member]
Debt Instrument [Line Items]
Conversion price per share (in dollars per share) | $ / shares	$ 294.54
Convertible Notes, threshold percentage of stock price trigger	130.00%
Convertible Notes per $1,000 principle, threshold percentage of stock price trigger	98.00%
Price per share of stock sold (in dollars per share) | $ / shares		$ 225.08
Cumulative dilutive effect when price of stock exceeds conversion price (in shares) | shares	1,026,000
Options Held [Member] | Class A Common Stock [Member]
Debt Instrument [Line Items]
Payments for convertible note hedges | $	$ 248,000,000
Hedging activity, shares covered | shares	4,490,020
Hedging activity, strike price (in dollars per share) | $ / shares	$ 294.54
Fair Value, Inputs, Level 2 [Member] | Convertible Debt [Member]
Debt Instrument [Line Items]
Estimated fair value of Notes | $		$ 1,382,000,000