Earnings Per Common Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income		$ 199,738	$ 157,870	$ 98,387
Net income applicable to non-vested restricted shares		(1,681)	(1,312)	(916)
Net income applicable to common shares		$ 198,057	$ 156,558	$ 97,471
Weighted-average common shares outstanding:
Weighted-average common shares outstanding (basic) (in shares)		108,156	102,850	101,423
Dilutive effect of common stock equivalents (in shares)		428	4	20
Weighted-average diluted common shares outstanding (in shares)		108,584	102,854	101,443
Basic EPS (in dollars per share)		$ 1.83	$ 1.52	$ 0.96
Diluted EPS (in dollars per share)		$ 1.82	$ 1.52	$ 0.96
Anti-dilutive shares not included in the computation of diluted EPS (in shares)	[1]	0	27	229

[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.