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Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended					12 Months Ended	15 Months Ended
	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2009	Mar. 31, 2018
Basic earnings per share:
Weighted-average common shares outstanding	29,659,454		29,560,521
Net income	$ 9,489		$ 4,427
Net income available to common stockholders	$ 9,489		$ 4,427
Basic earnings per share (in dollars per share)	$ 0.32		$ 0.15
Diluted earnings per share:
Weighted-average common shares outstanding	29,659,454		29,560,521
Diluted average common shares outstanding	30,168,748		29,940,950
Diluted earnings per share (in dollars per share)	$ 0.31		$ 0.15
Warrant term				10 years
Antidilutive options and warrants
Diluted earnings per share:
Dilutive effect of nonvested restricted awards (in shares)	36,358		2,317
One 10 year warrant			900,839
Warrants
Diluted earnings per share:
One 10 year warrant	815,339		815,339
Warrants, exercise price (in dollars per share)	$ 13.43		$ 13.43				$ 13.43
Warrant term		10 years			10 years	10 years	10 years
Restricted stock and restricted stock units
Diluted earnings per share:
Dilutive effect of nonvested restricted awards (in shares)	472,936		378,112