Earnings per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic earnings per share
Net income	$ 25,605	$ 16,322	$ 71,563	$ 51,313
Average common shares outstanding (in shares)	51,473	47,205	51,426	47,108
Net income per share (in dollars per share)	$ 0.50	$ 0.35	$ 1.39	$ 1.09
Diluted earnings per share
Average common shares outstanding (in shares)	51,473	47,205	51,426	47,108
Add: Dilutive effect of employee restricted stock and stock options (in shares)	462	824	570	795
Average diluted shares outstanding (in shares)	51,935	48,029	51,996	47,903
Net income per share (in dollars per share)	$ 0.49	$ 0.34	$ 1.38	$ 1.07