CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 1,322,143	$ 936,552
Short-term investments	60,007	9
Trade receivables and contract assets, net of allowance of $4,886 and $2,920, respectively	501,062	497,716
Prepaid and other current assets	29,570	39,934
Total current assets	1,912,782	1,474,211
Property and equipment, net	169,533	165,259
Operating lease right-of-use assets, net	228,672	238,991
Intangible assets, net	51,975	56,258
Goodwill	211,956	195,043
Deferred tax assets	92,454	75,013
Other noncurrent assets	53,960	39,433
Total assets	2,721,332	2,244,208
Current liabilities
Accounts payable	10,189	7,831
Accrued compensation and benefits expenses	294,709	230,035
Accrued expenses and other current liabilities	79,690	82,476
Income taxes payable, current	20,603	9,064
Operating lease liabilities, current	60,759	57,542
Total current liabilities	465,950	386,948
Long-term debt	25,038	25,074
Income taxes payable, noncurrent	43,448	45,878
Operating lease liabilities, noncurrent	180,604	180,848
Other noncurrent liabilities	23,274	9,315
Total liabilities	738,314	648,063
Commitments and contingencies (Note 15)
Stockholders’ equity
Common stock, $0.001 par value; 160,000 authorized; 56,128 and 55,208 shares issued, 56,108 and 55,188 shares outstanding at December 31, 2020 and December 31, 2019, respectively	56	55
Additional paid-in capital	660,771	607,051
Retained earnings	1,347,880	1,020,590
Treasury stock	(177)	(177)
Accumulated other comprehensive loss	(25,512)	(31,374)
Total stockholders’ equity	1,983,018	1,596,145
Total liabilities and stockholders’ equity	$ 2,721,332	$ 2,244,208