Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 36,066	$ 39,806	$ 79,741	$ 63,038
Preferred stock dividends	(10)	(10)	(20)	(20)
Net income available to common equity	36,056	39,796	79,721	63,018
Dividends and undistributed earnings allocated to participating securities	(34)	(49)	(67)	(71)
Net income available to common shareholders	$ 36,022	$ 39,747	$ 79,654	$ 62,947
Basic weighted-average shares outstanding (shares)	38,830	38,663	38,826	38,602
Stock options and other stock compensation (shares)	365	497	447	522
Diluted weighted-average shares outstanding (shares)	39,195	39,160	39,273	39,124
Antidilutive stock options (shares)	0	0	0	0
Earnings per share:
Basic (in dollars per share)	$ 0.93	$ 1.03	$ 2.05	$ 1.63
Diluted (in dollars per share)	$ 0.92	$ 1.01	$ 2.03	$ 1.61