Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Computation of Basic Earnings and Diluted Earnings Per Share Data

Basic earnings and diluted earnings per share data were computed as follows:

	Years Ended December 31,
	2017		2016		2015
Numerator for basic and diluted earnings per share:
Net income	$	163,945	$	109,857	$	64,869
Denominator:
Weighted-average basic common shares outstanding	37,273		36,448		34,137
Assumed conversion of dilutive securities:
Stock options	1,973		2,513		2,415
Denominator for diluted earnings per share    - Adjusted weighted-average shares	39,246		38,961		36,552
Earnings per common share:
Basic	$	4.40	$	3.01	$	1.90
Diluted	$	4.18	$	2.82	$	1.77