Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	14,017	20,116	12,182	9,375
Net Income	$ 24,986	$ 26,563	$ 60,728	$ 80,394
Weighted average number of common shares outstanding (for basic calculation)	20,948,000	20,666,000	20,870,000	20,607,000
Dilutive securities	608,000	821,000	691,000	949,000
Diluted (in shares)	21,556,000	21,487,000	21,561,000	21,556,000
EPS - basic	$ 1.19	$ 1.29	$ 2.91	$ 3.90
Diluted (In dollars per share)	$ 1.16	$ 1.24	$ 2.82	$ 3.73