UNEARNED REVENUE (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Changes in unearned revenue

Changes in unearned revenue were as follows:

December 31,	2018			2017
(in thousands)
Balance at beginning of year	$	117,614		$	106,323
Deferral of unearned revenue		166,053			151,139
Recognition of unearned revenue		(156,592	)		(139,848	)
Balance at December 31,	$	127,075		$	117,614