INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2015

INVESTMENTS

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

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	$	-
December 31, 2014	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	$	19,482	$	-	$	2	$	19,480	$	-	$	-
Municipal securities	744,542		105		-		744,647		-		-
U.S. government agency securities	9,199		-		1		9,198		-		-
Long-term:
Municipal securities	42,940		10		-		42,950		-		-
Available-for-sale
Variable rate demand notes	4,001		-		-		4,001		-		-
Total	$	820,164	$	115	$	3	820,276		$	-	$	-
Trading
Short-term:
Auction rate securities							3,910
Long-term:
Auction rate securities							-
Total							$	824,186

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

	2015		2014		2013
Gain (loss) on transfer from available-for-sale to trading	$	-	$	-	$	-
Gain on trading securities sold	250		978		255
(Loss) gain on trading securities held	-		(177)		816
Gain on trading securites	$	250	$	801	$	1,071

Summarizes the underlying contractual maturities of the Company's investments

	December 31, 2015				December 31, 2014
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than 1 year:
Commercial paper	$	3,978	$	3,978	$	19,482	$	19,480
Municipal securities	709,207		709,078		744,542		744,647
U.S. government agency securities	23,369		23,311		9,199		9,198
U.S. Treasuries	8,056		8,043		-		-
Due 1 -10 years:
Municipal securities	11,071		11,063		42,940		42,950
U.S. government agency securities	4,277		4,252		-		-
Due 11 - 20 years:
Auction rate securities	-		-		3,910		3,910
Due 21 - 30 years:
Variable rate demand notes	-		-		4,001		4,001
Total	$	759,958	$	759,725	$	824,074	$	824,186