OTHER ACCRUED LIABILITIES - Changes in Product Warranty Accrual (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 22,247	$ 20,132
Provision for warranties issued in current year	4,067	3,580
Payments	(2,805)	(2,671)
Balance at end of period	$ 23,509	$ 21,041