INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2016

INVESTMENTS

Summary of investments in available-for-sale and held-to-maturity

December 31, 2016	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value			Continuous Unrealized Loss Position less than 12 Months		Continuous Unrealized Loss Position greater than 12 Months
Available-for-sale
Short-term:
Commercial paper	$	40,382	$	-	$	-	$		40,382	$	-	$	-
Municipal securities	140,379		-		181		140,198			181		-
U.S. government agency securities	26,057		-		6		26,051			6		-
Variable rate demand notes	13,923		-		-		13,923			-		-
Long-term:
Municipal securities	2,403		-		9		2,394			9		-
Total	$	223,144	$	-	$	196	$		222,948	$	196	$	-
December 31, 2015	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value			Continuous Unrealized Loss Position less than 12 Months		Continuous Unrealized Loss Position greater than 12 Months
Held-to-Maturity
Short-term:
Commercial paper	$	3,978	$	-	$	-	$		3,978	$	-	$	-
Municipal securities	709,207		63		192		709,078			192		-
U.S. government agency securities	23,369		-		58		23,311			58		-
U.S. Treasuries	8,056		-		13		8,043			13		-
Long-term:
Municipal securities	11,071		-		8		11,063			8		-
U.S. government agency securities	4,277		-		25		4,252			25		-
Total	$	759,958	$	63	$	296	$	759,725		$	296	$	-

Summarizes the underlying contractual maturities of the Company's investments

	December 31, 2016				December 31, 2015
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than 1 year:
Commercial paper	$	40,382	$	40,382	$	3,978	$	3,978
Municipal securities	140,379		140,198		709,207		709,078
U.S. government agency securities	26,057		26,051		23,369		23,311
U.S. Treasuries	-		-		8,056		8,043
Due 1 -10 years:
Municipal securities	2,403		2,394		11,071		11,063
U.S. government agency securities	-		-		4,277		4,252
Variable rate demand notes	3,917		3,917		-		-
Due 11 - 20 years:
Variable rate demand notes	6,003		6,003		-		-
Due 21 - 30 years:
Variable rate demand notes	4,003		4,003		-		-
Total	$	223,144	$	222,948	$	759,958	$	759,725

Schedule of net gain (loss) recognized through earnings on trading securities

	2016		2015		2014
Gain (loss) on transfer from available-for-sale to trading	$	-	$	-	$	-
Gain on trading securities sold	-		250		978
(Loss) gain on trading securities held	-		-		(177)
Gain on trading securites	$	-	$	250	$	801