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						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Weighted-average shares:
Basic weighted-average common shares outstanding	35,939			35,569			35,829	35,525
Total weighted-average shares	36,037			35,710			35,930	35,669
Earnings per common share—Basic
Net income	$ 23,977	$ 27,455	$ 19,198	$ 19,305	$ 16,568	$ 14,551	$ 70,630	$ 50,424
Net income available to common shareholders—Basic	$ 23,912			$ 19,229			$ 70,431	$ 50,220
Net income per common share—Basic	$ 0.67			$ 0.54			$ 1.97	$ 1.41
Basic weighted-average common shares outstanding	35,939			35,569			35,829	35,525
Effect of diluted shares	1,896			1,556			1,678	1,270
Diluted weighted-average shares outstanding	37,835			37,125			37,507	36,795
Net income per common share—Diluted	$ 0.63			$ 0.52			$ 1.88	$ 1.36
RSAs
Weighted-average shares:
Basic weighted-average common shares outstanding	98			141			101	144
Earnings per common share—Basic
Less: Undistributed earnings allocated to RSAs	$ 65			$ 76			$ 199	$ 204
Basic weighted-average common shares outstanding	98			141			101	144
Common Stock
Weighted-average shares:
Basic weighted-average common shares outstanding	35,939			35,569			35,829	35,525
Earnings per common share—Basic
Basic weighted-average common shares outstanding	35,939			35,569			35,829	35,525