Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 53,017	$ 44,734	$ 159,909	$ 95,944
Earnings allocated to participating securities - nonvested restricted shares	91	164	317	487
Earnings allocated to common shareholders, Basic	$ 52,926	$ 44,570	$ 159,592	$ 95,457
Weighted average common shares outstanding	71,036	70,726	70,965	70,870
Basic earnings per common share	$ 0.75	$ 0.63	$ 2.25	$ 1.35
Earnings allocated to common shareholders, Diluted	$ 52,926	$ 44,570	$ 159,592	$ 95,457
Dilutive effect of equity awards	150	36	190	36
Weighted average diluted common shares outstanding	71,186	70,762	71,155	70,906
Diluted earnings per common share	$ 0.74	$ 0.63	$ 2.24	$ 1.35
Potentially dilutive stock awards and units that were not included in the computation of diluted EPS because to do so would be anti-dilutive.	269	596	198	487