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, 2018	Mar. 31, 2017
Weighted-average shares:
Basic weighted-average common shares outstanding	35,486	40,669
Total weighted-average shares	35,632	40,728
Earnings per common share—Basic
Net income	$ 14,551	$ 8,447
Net income available to common shareholders—Basic	$ 14,491	$ 8,435
Net income per common share—Basic	$ 0.41	$ 0.21
Basic weighted-average common shares outstanding	35,486	40,669
Effect of diluted shares	963	839
Diluted weighted-average shares outstanding	36,449	41,508
Net income per common share—Diluted	$ 0.40	$ 0.20
RSAs
Weighted-average shares:
Basic weighted-average common shares outstanding	146	59
Earnings per common share—Basic
Less: Undistributed earnings allocated to RSAs	$ 60	$ 12
Basic weighted-average common shares outstanding	146	59
Common Stock
Weighted-average shares:
Basic weighted-average common shares outstanding	35,486	40,669
Earnings per common share—Basic
Basic weighted-average common shares outstanding	35,486	40,669