COMMON STOCK REPURCHASES AND CASH DIVIDENDS Common Stock Repurchases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 30, 2018
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Value	$ 9,188	$ 6,435	$ 53,731
Common Stock [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 30,000		$ 60,000
Stock Repurchased and Retired During Period, Shares	129,000	146,000	1,300,000
Stock Repurchased and Retired During Period, Value	$ 9,200	$ 6,400	$ 53,700
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 44,400
Subsequent Event [Member] | Common Stock [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 30,000