Stock-Based Compensation - Summary of Changes in Number of Shares of Restricted Stock and Restricted Stock Units (Details)	6 Months Ended
	Jun. 30, 2020 $ / shares shares
Shares
Shares outstanding, beginning of period (in shares) | shares	243,000
Granted (in shares) | shares	151,000
Vested (in shares) | shares	(128,000)
Canceled or forfeited (in shares) | shares	(12,000)
Shares outstanding, end of period (in shares) | shares	254,000
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning of period (in dollars per share) | $ / shares	$ 246.34
Weighted average grant date fair value, granted (in dollars per share) | $ / shares	218.02
Weighted average grant date fair value, vested (in dollars per share) | $ / shares	222.49
Weighted average grant date fair value, canceled or forfeited (in dollars per share) | $ / shares	251.49
Weighted average grant date fair value, end of period (in dollars per share) | $ / shares	$ 240.08