Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 45,871	$ 39,970
Earnings allocated to participating securities - nonvested restricted shares	456	437
Earnings allocated to common shareholders, Basic	$ 45,415	$ 39,533
Weighted average common shares outstanding	72,521	72,300
Basic earnings per common share	$ 0.63	$ 0.55
Earnings allocated to common shareholders, Diluted	$ 45,415	$ 39,533
Dilutive effect of equity awards and warrants	3	5
Weighted average diluted common shares outstanding	72,524	72,305
Diluted earnings per common share	$ 0.63	$ 0.55
Potentially dilutive share options that were not included in the computation of diluted EPS because to do so would be anti-dilutive.	0	12