STATEMENT OF STOCKHOLDERS' EQUITY Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings
Beginning balance at Dec. 31, 2018		$ 28	$ 126,164	$ (1,689)	$ 402,569
Common stock issued under employee stock plans		0	5,678
Repurchase of common stock		0	(7,302)
Stock-based compensation			9,903
Other comprehensive income	$ 353			353
Net income	18,078
Payment of dividends to stockholders					(9,917)
Ending balance at Jun. 30, 2019	543,865	28	134,443	(1,336)	410,730
Beginning balance at Mar. 31, 2019		28	127,769	(1,361)	404,865
Common stock issued under employee stock plans		0	1,178
Repurchase of common stock		0	0
Stock-based compensation			5,496
Other comprehensive income	25			25
Net income	10,845
Payment of dividends to stockholders					(4,980)
Ending balance at Jun. 30, 2019	543,865	28	134,443	(1,336)	410,730
Beginning balance at Dec. 31, 2019	724,546	28	152,117	(3,130)	575,531
Common stock issued under employee stock plans		0	6,298
Repurchase of common stock	(2,600)	0	(2,636)
Stock-based compensation			12,691
Other comprehensive income	1,410			1,410
Net income	29,078
Payment of dividends to stockholders					(11,915)
Ending balance at Jun. 30, 2020	759,472	28	168,470	(1,720)	592,694
Beginning balance at Mar. 31, 2020		28	162,343	(4,314)	585,773
Common stock issued under employee stock plans		0	769
Repurchase of common stock		0	(623)
Stock-based compensation			5,981
Other comprehensive income	2,594			2,594
Net income	13,192
Payment of dividends to stockholders					(6,271)
Ending balance at Jun. 30, 2020	$ 759,472	$ 28	$ 168,470	$ (1,720)	$ 592,694