Stock-based Compensation - RSAs & Performance-Based RSUs (Details)	6 Months Ended
	Jun. 30, 2021 $ / shares shares
RSAs
Number of shares
Beginning balance (in shares) | shares	51,561
Granted (in shares) | shares	50,981
Vested (in shares) | shares	(32,210)
Forfeited (in shares) | shares	0
Ending balance (in shares) | shares	70,332
Weighted average price at grant
Beginning balance (in dollars per share) | $ / shares	$ 50.92
Granted (in dollars per share) | $ / shares	53.92
Vested (in dollars per share) | $ / shares	50.39
Forfeited (in dollars per share) | $ / shares	0
Ending balance (in dollars per share) | $ / shares	$ 53.34
RSUs
Number of shares
Beginning balance (in shares) | shares	87,787
Granted (in shares) | shares	31,749
Performance criteria adjustment (in shares) | shares	12,257
Vested (in shares) | shares	(38,897)
Forfeited (in shares) | shares	(1,954)
Ending balance (in shares) | shares	90,942
Weighted average price at grant
Beginning balance (in dollars per share) | $ / shares	$ 46.62
Granted (in dollars per share) | $ / shares	53.96
Performance criteria adjustment (in dollars per share) | $ / shares	52.96
Vested (in dollars per share) | $ / shares	52.96
Forfeited (in dollars per share) | $ / shares	35.40
Ending balance (in dollars per share) | $ / shares	$ 52.71