Stock-Based Compensation - Summary of PSU Activity (Details) - Performance-Based Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Units
Balance at the beginning of the period (in shares)	108,140	58,806	30,071
Granted (in shares)	45,242	49,334	28,735
Released (in shares)	(47,516)
Balance at the end of the period (in shares)	105,866	108,140	58,806
Weighted-Average Grant-Date Fair Value
Balance at the beginning of the period (in dollars per share)	$ 95.94	$ 89.87	$ 83.84
Granted (in dollars per share)	129.38	103.18	96.19
Released (in dollars per share)	112.16
Balance at the end of the period (in dollars per share)	$ 102.95	$ 95.94	$ 89.87