Earnings Per Common Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income		$ 157,870	$ 98,387	$ 92,349
Net income applicable to non-vested restricted shares		(1,312)	(916)	(1,043)
Net income applicable to common shares		$ 156,558	$ 97,471	$ 91,306
Weighted-average common shares outstanding:
Weighted-average common shares outstanding (basic) (in shares)		102,850	101,423	79,797
Dilutive effect of common stock equivalents (in shares)		4	20	13
Weighted-average diluted common shares outstanding (in shares)		102,854	101,443	79,810
Basic EPS (in dollars per share)		$ 1.52	$ 0.96	$ 1.14
Diluted EPS (in dollars per share)		$ 1.52	$ 0.96	$ 1.14
Anti-dilutive shares not included in the computation of diluted EPS (in shares)	[1]	27	229	494

[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. The final outstanding stock options were exercised during the first quarter of 2018.