EQUITY INSTRUMENTS (Schedule of Share-Based Compensation, Stock Options Activity) (Details) - Stock Option [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Shares
Number of Shares, Stock Option Outstanding, Beginning of Period	577,000	726,000	892,000
Number of Shares, Stock Option, Granted	0	140,000	194,000
Number of Shares, Stock Option, Exercised	(271,000)	(286,000)	(335,000)
Number of Shares, Stock Option, Forfeited/expired	0	(3,000)	(25,000)
Number of Shares, Stock Option Outstanding, End of Period	306,000	577,000	726,000
Number of Shares, Stock Option Exercisable	130,000
Number of Shares, Stock Option Vested and expected to vest	303,000
Weighted-Average Exercise Price Per Share
Weighted-Average Exercise Price Per Share, Stock Option Outstanding	$ 16.04	$ 12.60	$ 9.97
Weighted-Average Exercise Price Per Share, Stock Option, Granted	0	20.94	19.82
Weighted-Average Exercise Price Per Share, Stock Option, Exercised	15.76	9.65	9.50
Weighted-Average Exercise Price Per Share, Stock Option, Forfeited/expired	0	20.94	16.54
Weighted-Average Exercise Price Per Share, Stock Option Outstanding	16.28	$ 16.04	$ 12.60
Weighted-Average Exercise Price Per Share, Stock Option Exercisable	12.52
Weighted-Average Exercise Price Per Share, Stock Option Vested and expected to vest	$ 16.25
Weighted-Average Remaining Contractual Life (in Years)
Weighted-Average Remaining Contractual Life (years), Stock Option Outstanding	3 years 9 months 10 days
Weighted-Average Remaining Contractual Life (years), Stock Option Exercisable	3 years 7 days
Weighted-Average Remaining Contractual Life (years), Stock Option Vested and expected to vest	3 years 9 months 10 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Stock Option Outstanding	$ 11,121
Aggregate Intrinsic Value, Stock Option Exercisable	5,230
Aggregate Intrinsic Value, Stock Option Vested and expected to vest	$ 11,029