Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income per share calculations for basic and diluted methods
Net income available to common stockholders	$ 25,469	$ 21,917
Shares:
Weighted average common shares outstanding	53,277,000	48,775,000
Dilutive effect of outstanding options, warrants and restricted stock units as determined by the application of the treasury stock method (in shares)	301,000	404,000
Weighted average common shares outstanding, as adjusted for diluted earnings per share calculation	53,578,000	49,179,000
Basic earnings per common share (in dollars per share)	$ 0.48	$ 0.45
Diluted earnings per common share (in dollars per share)	$ 0.48	$ 0.45
Stock options
Anti-dilutive securities excluded from the calculation of common stock equivalents
Number of anti-dilutive securities (in shares)	49,646
RSU
Anti-dilutive securities excluded from the calculation of common stock equivalents
Number of anti-dilutive securities (in shares)	172,571
Warrants
Anti-dilutive securities excluded from the calculation of common stock equivalents
Number of anti-dilutive securities (in shares)	191,278	191,278