SHAREHOLDERS EQUITY - Summary of Dividend payments (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended														6 Months Ended	12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stockholders' Equity Note [Abstract]
Record Date	Jun. 15, 2015	Mar. 16, 2015	Dec. 08, 2014	Sep. 15, 2014	Jun. 16, 2014	Mar. 17, 2014	Dec. 09, 2013	Sep. 16, 2013	Jun. 17, 2013	Mar. 18, 2013	Dec. 10, 2012	Sep. 17, 2012	Jun. 18, 2012	Mar. 19, 2012
Payment Date	Jun. 22, 2015	Mar. 23, 2015	Dec. 15, 2014	Sep. 22, 2014	Jun. 23, 2014	Mar. 24, 2014	Dec. 16, 2013	Sep. 23, 2013	Jun. 24, 2013	Mar. 25, 2013	Dec. 17, 2012	Sep. 24, 2012	Jun. 25, 2012	Mar. 26, 2012
Dividend (per share)	$ 0.16	$ 0.16	$ 0.15	$ 0.15	$ 0.15	$ 0.15	$ 0.14	$ 0.14	$ 0.14	$ 0.14	$ 0.13	$ 0.13	$ 0.13	$ 0.13	$ 0.32	$ 0.60	$ 0.56	$ 0.52
Dividend paid, amount	$ 1,814	$ 1,809	$ 1,695	$ 1,696	$ 1,695	$ 1,692	$ 1,577	$ 1,575	$ 1,573	$ 1,569	$ 1,447	$ 1,439	$ 1,439	$ 1,437	$ 3,623	$ 6,778	$ 6,294	$ 5,762