SHAREHOLDERS' EQUITY (Reconciliation of Changes in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands			3 Months Ended
	Jan. 01, 2019	Jan. 01, 2018	Mar. 31, 2019	Mar. 31, 2018
Net
Accumulated other comprehensive income (loss), beginning-of-period	$ (3,750)		$ (3,750)
Accumulated other comprehensive income (loss), end-of-period			3,138
AOCI Attributable to Parent
Before Tax
Accumulated other comprehensive income (loss), beginning-of-period	(5,023)	$ 2,287	(5,023)	$ 2,287
Cumulative effect of new accounting standards	0	(1,349)
Other comprehensive income (loss) before reclassification			11,528	(7,200)
Reclassification adjustment for realized losses (gains) included in net income			(2,301)	1,052
Comprehensive income (loss)			9,227	(6,148)
Accumulated other comprehensive income (loss), end-of-period			4,204	(5,210)
Income Tax
Accumulated other comprehensive income (loss), beginning-of-period	1,273	(593)	1,273	(593)
Cumulative effect of new accounting standards	0	355
Other comprehensive income (loss) before reclassification			(2,922)	1,825
Reclassification adjustment for realized losses (gains) included in net income			583	(238)
Other Comprehensive Income (Loss), Tax			(2,339)	1,587
Accumulated other comprehensive income (loss), end-of-period			(1,066)	1,349
Net
Accumulated other comprehensive income (loss), beginning-of-period	(3,750)	1,694	(3,750)	1,694
Cumulative effect of new accounting standards	$ 0	$ (994)
Other comprehensive income (loss) before reclassification			8,606	(5,375)
Reclassification adjustment for realized losses (gains) included in net income			(1,718)	814
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent			6,888	(4,561)
Accumulated other comprehensive income (loss), end-of-period			$ 3,138	$ (3,861)