Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 223,063	$ 369,373
Accounts receivable:
Billed receivables	584,620	540,584
Unbilled receivables	436,944	418,288
Allowance for doubtful accounts and unbilled services	(284,666)	(265,500)
Accounts receivable, net	736,898	693,372
Current portion of notes receivable	31,942	35,106
Prepaid expenses and other current assets	74,544	80,810
Total current assets	1,066,447	1,178,661
Property and equipment, net	92,852	93,672
Operating lease assets	149,570	159,777
Goodwill	1,191,948	1,202,767
Other intangible assets, net	35,682	38,432
Notes receivable, net	63,801	69,033
Other assets	36,881	40,800
Total assets	2,637,181	2,783,142
Current liabilities
Accounts payable, accrued expenses and other	170,930	158,936
Accrued compensation	240,192	416,903
Billings in excess of services provided	40,219	36,698
Total current liabilities	451,341	612,537
Long-term debt, net	328,193	275,609
Noncurrent operating lease liabilities	163,594	176,378
Deferred income taxes	152,347	151,352
Other liabilities	73,022	78,124
Total liabilities	1,168,497	1,294,000
Commitments and contingent liabilities (Note 10)
Stockholders' equity
Preferred stock, $0.01 par value; shares authorized — 5,000; none outstanding	0	0
Common stock, $0.01 par value; shares authorized — 75,000; shares issued and outstanding — 37,110 (2020) and 37,390 (2019)	371	374
Additional paid-in capital	170,062	216,162
Retained earnings	1,470,200	1,413,453
Accumulated other comprehensive loss	(171,949)	(140,847)
Total stockholders' equity	1,468,684	1,489,142
Total liabilities and stockholders' equity	$ 2,637,181	$ 2,783,142