Earnings Per Share - Reconciliation of Basic and Diluted Shares Amounts (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator
Net income	$ 49,861	$ 36,233	$ 96,825	$ 65,683
Effect of dilutive securities
Charges associated with convertible debt instruments, net of tax	0	0	387	0
Numerator for diluted earnings per share - net income available to common stockholders after the effect of dilutive securities	$ 49,861	$ 36,233	$ 97,212	$ 65,683
Denominator
Weighted average shares used in computing net income per share - basic	55,444	54,931	55,399	54,868
Effect of dilutive shares
Options and stock units	598	843	661	903
Convertible senior notes	676	1,012	1,779	1,052
Dilutive effect of unvested performance stock units	3	0	3	0
Dilutive potential common shares	1,277	1,855	2,443	1,956
Denominator for diluted earnings per share - adjusted weighted average shares used in computing net income per share - diluted	56,721	56,786	57,842	56,824
Earnings per share:
Basic	$ 0.90	$ 0.66	$ 1.75	$ 1.20
Diluted (Note 12)	$ 0.88	$ 0.64	$ 1.68	$ 1.16