Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 456,799	$ 352,917
Marketable securities	831,260	745,156
Accounts receivable, net of reserves of $1,654 and $1,822 at March 31, 2021, and December 31, 2020, respectively	666,536	660,052
Prepaid expenses and other current assets	206,807	171,406
Total current assets	2,161,402	1,929,531
Marketable securities	1,165,573	1,398,802
Property and equipment, net	1,511,393	1,478,272
Operating lease right-of-use assets	825,944	793,945
Acquired intangible assets, net	227,436	234,724
Goodwill	1,682,093	1,674,371
Deferred income tax assets	103,433	106,918
Other assets	140,646	147,567
Total assets	7,817,920	7,764,130
Current liabilities:
Accounts payable	119,462	118,546
Accrued expenses	309,894	380,468
Deferred revenue	102,525	76,600
Operating lease liabilities	156,656	154,801
Other current liabilities	26,594	27,755
Total current liabilities	715,131	758,170
Deferred revenue	4,076	5,262
Deferred income tax liabilities	35,115	37,458
Convertible senior notes	1,923,829	1,906,707
Operating lease liabilities	733,544	715,404
Other liabilities	84,862	89,833
Total liabilities	3,496,557	3,512,834
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value; 5,000,000 shares authorized; 700,000 shares designated as Series A Junior Participating Preferred Stock; no shares issued or outstanding	0	0
Common stock, $0.01 par value; 700,000,000 shares authorized; 163,837,904 shares issued and 163,245,941 shares outstanding at March 31, 2021, and 162,709,720 shares issued and outstanding at December 31, 2020	1,638	1,627
Additional paid-in capital	3,664,568	3,664,820
Accumulated other comprehensive loss	(47,347)	(20,201)
Treasury stock, at cost, 591,963 shares at March 31, 2021, and no shares at December 31, 2020	(58,241)	0
Retained earnings	760,745	605,050
Total stockholders’ equity	4,321,363	4,251,296
Total liabilities and stockholders’ equity	$ 7,817,920	$ 7,764,130