Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Basic and Diluted Earnings Per Share
Net income available to common stockholders, basic and diluted	$ 52,392	$ 44,384	$ 101,524	$ 82,943
Average outstanding shares - basic	85,826,290	84,514,257	85,191,658	82,671,816
Add: dilutive restricted stock awards and stock options	31,996	45,011	49,580	62,591
Average outstanding shares - diluted	85,858,286	84,559,268	85,241,238	82,734,407
Basic earnings per share	$ 0.61	$ 0.53	$ 1.19	$ 1.00
Diluted earnings per share	$ 0.61	$ 0.52	$ 1.19	$ 1.00
Earnings Per Share
Restricted stock awards and stock options excluded from the diluted average outstanding share calculation	0	0	0	0