Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Earnings Per Share [Abstract]
Weighted average stock options excluded (in shares)	0	1,228	0
Net Income
Basic income available to common stockholders	$ 28,002	$ 16,171	$ 9,521
Diluted income available to common stockholders plus assumed conversions	$ 28,002	$ 16,171	$ 9,521
Shares
Basic income available to common stockholders (in shares)	45,893,496	43,797,403	27,528,940
Dilutive effect of share-based compensation (in shares)	758,563	816,945	668,280
Diluted income available to common stockholders plus assumed conversions (in shares)	46,652,059	44,614,348	28,197,220
Per Share Amount
Basic income available to common stockholders (in dollars per share)	$ 0.61	$ 0.37	$ 0.35
Diluted income available to common stockholders plus assumed conversions (in dollars per share)	$ 0.60	$ 0.36	$ 0.34