EARNINGS PER SHARE - Stock Buyback (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Sep. 30, 2015	Mar. 31, 2020	Jun. 30, 2020	Dec. 18, 2019	May 31, 2018
EARNINGS PER SHARE
Authorized amount	$ 150,000
Authorized program period repurchase	30 months
Authorized amount increase				$ 25,100	$ 50,000
Remaining authorized repurchase amount			$ 42,800
Amount paid to repurchase shares		$ 7,248	$ 7,248
Number of shares repurchased			170
Average repurchase price per share			$ 42.59