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 [Abstract]
Net income		$ 33,510	$ 22,855
Net income applicable to non-vested restricted shares		(311)	(234)
Net income applicable to common shares		$ 33,199	$ 22,621
Weighted-average common shares outstanding:
Weighted-average common shares outstanding (basic) (in Shares)		101,922	100,411
Dilutive effect of common stock equivalents (in Shares)		16	21
Weighted-average diluted common shares outstanding (in Shares)		101,938	100,432
Basic EPS (in dollars per share)		$ 0.33	$ 0.23
Diluted EPS (in dollars per share)		$ 0.33	$ 0.23
Anti-dilutive shares not included in the computation of diluted EPS (in Shares)	[1]	110	343

[1] This amount represents outstanding stock options for which the exercise price is greater than the average market price of the Company's common stock.