Employee Benefit Plans - Summary of Stock Options and Related Activity (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Options outstanding, shares
Options outstanding, Beginning balance (in shares)	23,910,062
Granted (in shares)	1,539,861
Exercised (in shares)	(2,977,250)
Expired (in shares)	0
Forfeited (in shares)	(722,634)
Options outstanding, Ending balance (in shares)	21,750,039	23,910,062
Options exercisable, Ending balance (in shares)	15,620,920
Options Outstanding, Weighted Average Exercise Price
Options outstanding, weighted average exercise price, Beginning balance (in usd per share)	$ 9.81
Granted (in usd per share)	$ 23.94
Exercised (in usd per share)	$ 9.55
Expired (in usd per share)	$ 0.00
Forfeited (in usd per share)	$ (12.36)
Options outstanding, Weighted average exercise price, Ending balance (in usd per share)	$ 10.76	$ 9.81
Options exercisable, Weighted average exercise price, Ending balance (in usd per share)	$ 9.87
Weighted-Average Remaining Contractual Term (Years)
Options outstanding, weighted average remaining contractual term (Years)	7 years 8 months	8 years
Options exercisable, weighted average remaining contractual term (Years)	7 years 6 months
Aggregate Intrinsic Value
Aggregate intrinsic value, Exercised	$ (43,836)
Options outstanding, aggregate intrinsic value	188,766
Options exercisable, aggregate intrinsic value	$ 149,421