CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 762,529	$ 770,560
Accounts receivable, net of allowance of $1,415 and $1,557, respectively	307,202	297,685
Unbilled revenues	144,152	104,652
Prepaid and other current assets	30,864	26,171
Total current assets	1,244,747	1,199,068
Property and equipment, net	105,805	102,646
Operating lease right-of-use assets	173,091	0
Intangible assets, net	50,087	57,065
Goodwill	167,707	166,832
Deferred tax assets	69,345	69,983
Other noncurrent assets	20,653	16,208
Total assets	1,831,435	1,611,802
Current liabilities
Accounts payable	4,397	7,444
Accrued expenses and other current liabilities	72,793	127,937
Due to employees	86,012	49,683
Deferred compensation due to employees	9,673	9,920
Taxes payable, current	69,835	67,845
Operating lease liabilities, current	39,856	0
Total current liabilities	282,566	262,829
Long-term debt	25,000	25,031
Taxes payable, noncurrent	43,679	43,685
Operating lease liabilities, noncurrent	127,935	0
Other noncurrent liabilities	14,030	17,661
Total liabilities	493,210	349,206
Commitments and contingencies (Note 11)
Stockholders’ equity
Common stock, $0.001 par value; 160,000,000 authorized; 54,584,243 and 54,099,927 shares issued, 54,564,508 and 54,080,192 shares outstanding at March 31, 2019 and December 31, 2018, respectively	54	54
Additional paid-in capital	553,532	544,700
Retained earnings	820,287	759,533
Treasury stock	(177)	(177)
Accumulated other comprehensive loss	(35,471)	(41,514)
Total stockholders’ equity	1,338,225	1,262,596
Total liabilities and stockholders’ equity	$ 1,831,435	$ 1,611,802