Stock-Based Compensation - Non-Vested Restricted Stock Award Activity (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Shares
Non-vested at beginning of period (in shares) | shares	374
Granted (in shares) | shares	153
Vested (in shares) | shares	(195)
Forfeited (in shares) | shares	(7)
Non-vested at end of period (in shares) | shares	325
Weighted-Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 34.53
Granted (in dollars per share) | $ / shares	57.32
Vested (in dollars per share) | $ / shares	35.88
Forfeited (in dollars per share) | $ / shares	37.85
Non-vested at end of period (in dollars per share) | $ / shares	$ 44.38