COMMON STOCK Schedule of Changes in SARs (Details) - Stock Appreciation Rights (SARs) [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of SARs
Outstanding beginning of year, January 1,	326,453	279,011	190,763
Awarded	58,709	68,274	88,248
Exercised	(141,084)	(20,832)	0
Outstanding end of year, December 31,	244,078	326,453	279,011
Exercisable at December 31,				174,919	222,489	139,334
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding beginning of year, January 1,	$ 38.99	$ 38.77	$ 33.77
Awarded	51.63	39.63	49.57
Exercised	40.16	38.05	0
Outstanding end of year, December 31,	$ 41.36	$ 38.99	$ 38.77
Exercisable at December 31,				$ 38.72	$ 37.70	$ 36.27
Weighted-Average Remaining Contractual Term (in years)
Outstanding at December 31,	6 years 10 months 19 days	7 years 3 months 6 days
Exercisable at December 31,	6 years 3 months 10 days
Share based compesation aggregate intrinsic valu [Roll Forward]
Outstanding beginning of year, January 1,	$ 7,620	$ 4,697	$ 1,472	$ 7,620	$ 4,697	$ 1,472	$ 3,711
Awarded	0	0	0
Exercised	2,770	473	0
Outstanding end of year, December 31,	$ 7,620	$ 4,697	$ 1,472
Exercisable at December 31,				5,924	$ 3,489	$ 982
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized				$ 1,500
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	1 year 8 months 22 days