SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Common Stock Repurchases and Common Stock Dividend) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	3 Months Ended												12 Months Ended
	Jan. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Cost of shares repurchased														$ 6,435	$ 53,731	$ 80,761
Common stock dividends declared		$ 0.13	$ 0.13	$ 0.13	$ 0.13	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.10	$ 0.10
Common Stock [Member]
Class of Stock [Line Items]
Stock Repurchase Authorization Increase Value															$ 60,000	$ 75,000
Number of shares repurchased														0.1	1.3	1.6
Cost of shares repurchased														$ 6,400	$ 53,700	$ 80,800
Remaining authorized repurchase amount		$ 23,600												$ 23,600
Subsequent Event [Member]
Class of Stock [Line Items]
Common stock dividends declared, payable 1st quarter 2016	$ 0.14
Common stock dividends declared, payable 2nd quarter 2016	0.14
Common stock dividends declared, payable 3rd quarter 2016	0.14
Common stock dividends declared, payable 4th quarter 2016	$ 0.14