Stockholders' Equity - Range Of Exercise Prices (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) $ / shares shares
2009 Stock Option Plan
Outstanding at ending of the year (in shares) | shares	251,330
Weighted Avg. Exercise Price (in dollars per share)	$ 35.28
Weighted Avg. Remaining Contractual Life	6 years 9 months 18 days
Total Intrinsic Value | $	$ 6,252
Vested options
2009 Stock Option Plan
Outstanding at ending of the year (in shares) | shares	101,941
Weighted Avg. Exercise Price (in dollars per share)	$ 27.88
Weighted Avg. Remaining Contractual Life	5 years
Total Intrinsic Value | $	$ 3,291
$23.00-$28.00
2009 Stock Option Plan
Exercise prices, low end of range (in dollars per share)	$ 23.00
Exercise prices, high end of range (in dollars per share)	$ 28.00
Outstanding at ending of the year (in shares) | shares	111,313
Weighted Avg. Exercise Price (in dollars per share)	$ 26.25
Weighted Avg. Remaining Contractual Life	4 years 10 months 24 days
Total Intrinsic Value | $	$ 3,775
$28.00-$32.00
2009 Stock Option Plan
Exercise prices, low end of range (in dollars per share)	$ 28.00
Exercise prices, high end of range (in dollars per share)	$ 32.00
Outstanding at ending of the year (in shares) | shares	14,073
Weighted Avg. Exercise Price (in dollars per share)	$ 29.84
Weighted Avg. Remaining Contractual Life	4 years 3 months 18 days
Total Intrinsic Value | $	$ 427
$32.00 - $47.00
2009 Stock Option Plan
Exercise prices, low end of range (in dollars per share)	$ 32.00
Exercise prices, high end of range (in dollars per share)	$ 47.00
Outstanding at ending of the year (in shares) | shares	125,944
Weighted Avg. Exercise Price (in dollars per share)	$ 43.88
Weighted Avg. Remaining Contractual Life	8 years 8 months 12 days
Total Intrinsic Value | $	$ 2,050