Earnings Per Share (EPS Components) (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
Summary of earnings per share
Net income	$ 34,873	$ 51,845	$ 86,526	$ 117,698
Weighted Average Shares (in shares)
BASIC SHARES	32,951,918	34,361,176	33,358,879	32,283,196
EFFECT OF DILUTIVE SECURITIES	24,758	39,390	27,871	45,416
DILUTIVE SHARES	32,976,676	34,400,566	33,386,750	32,328,612
NET INCOME PER SHARE (in dollars per share)
BASIC EPS	$ 1.06	$ 1.51	$ 2.59	$ 3.65
EFFECT OF DILUTIVE SECURITIES	0	0	0	(0.01)
DILUTIVE EPS	$ 1.06	$ 1.51	$ 2.59	$ 3.64