Note 1 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Schedule of Cash and Cash Equivalents [Table Text Block]

Year ended December 31,	2020		2019			2018
Cash, cash equivalents and restricted cash, beginning of period	$	268,108	$	278,629		$	233,711
End of the period
Cash and cash equivalents		436,136		262,273			272,804
Restricted cash		1,512		5,835			5,825
Total cash, cash equivalents and restricted cash, end of period		437,648		268,108			278,629
Net increase (decrease) in cash, cash equivalents and restricted cash	$	169,540	$	(10,521	)	$	44,918