Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Weighted average number of stock options excluded (in shares)									17,524	82,760	222,858
Income/(Loss) (numerator)
Net income applicable to earnings per share									$ 60,100	$ 40,103	$ 25,515
Basic earnings per share: Income available to common stockholders	$ 16,171	$ 20,232	$ 14,176	$ 9,521	$ 11,953	$ 9,227	$ 10,369	$ 8,554	60,100	40,103	25,515
Diluted earnings per share: Income available to common stockholders									$ 60,100	$ 40,103	$ 25,515
Shares (denominator)
Basic earnings per share: Income available to common stockholders (in shares)									37,705,556	26,931,634	21,156,668
Effect of dilutive securities: Warrants and stock option plans (in shares)									805,705	507,525	332,030
Diluted earnings per share: Income available to common stockholders (in shares)									38,511,261	27,439,159	21,488,698
Per Share Amount
Basic earnings per share: Income available to common stockholders (in dollars per share)	$ 0.37	$ 0.51	$ 0.36	$ 0.35	$ 0.44	$ 0.34	$ 0.38	$ 0.33	$ 1.59	$ 1.49	$ 1.21
Diluted earnings per share: Income available to common stockholders plus assumed conversions (in dollars per share)	$ 0.36	$ 0.50	$ 0.35	$ 0.34	$ 0.43	$ 0.33	$ 0.37	$ 0.33	$ 1.56	$ 1.46	$ 1.19