Net Income Per Share - Schedule of Reconciliation of Denominators and Additional Shares that are Excluded from the Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Weighted-average shares:
Basic weighted-average common shares outstanding	35,698	35,486
Total weighted-average shares	35,802	35,632
Earnings per common share—Basic
Net income	$ 19,198	$ 14,551
Net income available to common shareholders—Basic	$ 19,142	$ 14,491
Net income per common share—Basic	$ 0.54	$ 0.41
Basic weighted-average common shares outstanding	35,698	35,486
Effect of diluted shares	1,587	963
Diluted weighted-average shares outstanding	37,285	36,449
Net income per common share—Diluted	$ 0.51	$ 0.40
RSAs
Weighted-average shares:
Basic weighted-average common shares outstanding	104	146
Earnings per common share—Basic
Less: Undistributed earnings allocated to RSAs	$ 56	$ 60
Basic weighted-average common shares outstanding	104	146
Common Stock
Weighted-average shares:
Basic weighted-average common shares outstanding	35,698	35,486
Earnings per common share—Basic
Basic weighted-average common shares outstanding	35,698	35,486