Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 39,970	$ 29,199
Earnings allocated to participating securities - preferred shares	0	3
Earnings allocated to participating securities - nonvested restricted shares	437	397
Earnings allocated to common shareholders, Basic	$ 39,533	$ 28,799
Weighted average common shares outstanding	72,300	57,388
Basic earnings per common share	$ 0.55	$ 0.50
Earnings allocated to common shareholders, Diluted	$ 39,533	$ 28,799
Dilutive effect of equity awards and warrants	5	6
Weighted average diluted common shares outstanding	72,305	57,394
Diluted earnings per common share	$ 0.55	$ 0.50
Potentially dilutive share options that were not included in the computation of diluted EPS because to do so would be anti-dilutive.	12	14