Stock-Based Compensation - Summary of Changes in Number of Shares of Restricted Stock and Restricted Stock Units (Details) shares in Thousands	6 Months Ended
	Jun. 30, 2017 $ / shares shares
Shares
Shares outstanding, beginning of period (in shares) | shares	379
Granted (in shares) | shares	136
Vested (in shares) | shares	(200)
Canceled (in shares) | shares	(38)
Shares outstanding, end of period (in shares) | shares	277
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning of period (in dollars per share) | $ / shares	$ 140.39
Weighted average grant date fair value, granted (in dollars per share) | $ / shares	149.94
Weighted average grant date fair value, vested (in dollars per share) | $ / shares	136.22
Weighted average grant date fair value, canceled (in dollars per share) | $ / shares	155.55
Weighted average grant date fair value, end of period (in dollars per share) | $ / shares	$ 148.57