Stock-Based Compensation - Restricted Stock Units (Details) - Restricted Stock Units $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares
Shares
Unvested restricted at the beginning of the period (in shares) | shares	60,000
Granted (in shares) | shares	480,995
Forfeited (in shares) | shares	(3,700)
Unvested restricted at the end of the period (in shares) | shares	537,295
Weighted-average grant date fair value per share
Unvested restricted at the beginning of the period (in dollars per share) | $ / shares	$ 56.00
Granted (in dollars per share) | $ / shares	43.31
Forfeited (in dollars per share) | $ / shares	43.39
Unvested restricted at the end of the period (in dollars per share) | $ / shares	$ 44.72
Additional disclosure
Unrecognized compensation costs | $	$ 19.4
Weighted average period over which unrecognized compensation costs are expected to be recognized	3 years 9 months 18 days