Share-Based Compensation and Warrants - Additional Information (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 09, 2014	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value for the options granted					$ 41.75
Unrecognized compensation costs related to non-vested stock options		$ 6,000,000		$ 6,000,000
Expected weighted average period to recognize compensation cost on restricted stock (in years)				9 months 18 days
Compensation expense recognized for outstanding share-based awards		1,000,000	1,000,000	2,000,000	3,100,000
Number of shares that may be purchased with Company issued warrants		160,408		160,408
Exercise price of warrants		$ 1.00		$ 1.00
Warrants expiration date				2020-05
Number of warrants repurchased		117,050		117,050
Payments for repurchase of warrants				7,500,000
Number of warrants outstanding and exercisable		43,358		43,358
Outstanding Warrants Exercised	43,358
Issuance of common stock		1,029,072		1,029,072		985,714
Proceeds from exercise of warrants and stock options	$ 43,358			$ 43,000
Warrants Exercised
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock	43,358