Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 28,034	$ 42,239	$ 107,763	$ 105,278
Preferred stock dividends	(10)	(10)	(30)	(30)
Net income available to common equity	28,024	42,229	107,733	105,248
Dividends and undistributed earnings allocated to participating securities	(12)	(88)	(79)	(159)
Net income available to common shareholders	$ 28,012	$ 42,141	$ 107,654	$ 105,089
Basic weighted-average shares outstanding (shares)	38,906	38,649	38,853	38,617
Stock options and other stock compensation (shares)	354	495	416	513
Diluted weighted-average shares outstanding (shares)	39,260	39,144	39,269	39,130
Antidilutive stock options (shares)	0	0	0	0
Earnings per share:
Basic (in dollars per share)	$ 0.72	$ 1.09	$ 2.77	$ 2.72
Diluted (in dollars per share)	$ 0.71	$ 1.08	$ 2.74	$ 2.69