Earnings Per Share - (Reconciliation of Basic and Diluted Shares Amounts) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income	$ 15,861	$ 8,095	$ 25,676	$ 16,148
Weighted average shares used in computing net income per share - basic	52,381	46,367	52,260	45,174
Effect of dilutive shares:
Stock options and restricted stock awards	925	791	953	760
Convertible senior notes		1,898		1,758
Dilutive potential common shares	925	2,689	953	2,518
Weighted average shares used in computing net income per share - diluted	53,306	49,056	53,213	47,692
Earnings per share:
Basic	$ 0.30	$ 0.17	$ 0.49	$ 0.36
Diluted	$ 0.30	$ 0.17	$ 0.48	$ 0.34