Note 8 - Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Net Funded Status [Table Text Block]

	December 31,
	2017			2016
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	$	114,976		$	103,199
Interest cost		4,669			4,398
Actuarial losses		-			1,839
Benefits paid		(3,529	)		(2,790	)
Merger of assumed plans		9,970			8,330
Projected benefit obligation at end of year	$	126,086		$	114,976
Change in plan assets:
Fair value of pension plan assets at beginning of year	$	80,929		$	69,246
Actual return on plan assets		7,724			5,918
Company contributions		3,124			2,775
Benefits paid		(3,529	)		(2,790	)
Merger of assumed plans		-			5,780
Fair value of pension plan assets at end of year		88,248			80,929
Funded status of pension plan	$	(37,838	)	$	(34,047	)
Amounts recognized on our balance sheets consist of:
Accrued benefit cost	$	(1,502	)	$	(5,121	)
Accumulated other comprehensive loss		(36,336	)		(28,926	)
Net liability recognized	$	(37,838	)	$	(34,047	)

Schedule of Assumptions Used [Table Text Block]

	Year Ended December 31,
	2017			2016
Weighted-average assumptions used to determine net periodic benefit cost for the Gray Pension Plan:
Discount rate		4.11	%		4.31	%
Expected long-term rate of return on pension plan assets		7.00	%		7.00	%
Estimated rate of increase in compensation levels		N/A			N/A

	As of December 31,
	2017			2016
Weighted-average assumptions used to determine benefit obligations:
Discount rate		3.55	%		4.11	%

Schedule of Net Benefit Costs [Table Text Block]

	Year Ended December 31,
	2017			2016			2015
Components of net periodic pension cost:
Service cost	$	-		$	-		$	3,130
Interest cost		4,670			4,398			4,159
Expected return on plan assets		(5,648	)		(4,836	)		(4,782	)
Recognized net actuarial loss		484			406			1,580
Net periodic pension (benefit) cost	$	(494	)	$	(32	)	$	4,087

Schedule of Expected Benefit Payments [Table Text Block]

Years			Amount
2018			$	2,924
2019				3,279
2020				3,768
2021				4,047
2022				4,324
2023	-	2027		26,680

Schedule of Allocation of Plan Assets [Table Text Block]

	Target Range
Asset class:	Strategic Allocation			Lower Limit		Upper Limit
Equities:
Large cap value		5	%		0%		50	%
Large cap blend		5	%		0%		50	%
Large cap growth		5	%		0%		50	%
Mid cap blend		15	%		0%		40	%
Small cap core		5	%		0%		25	%
Foreign large blend		10	%		0%		40	%
Emerging markets		10	%		0%		25	%
Real estate		5	%		0%		20	%
Fixed Income:
U.S. Treasury inflation protected		5	%		0%		25	%
Intermediate term bond		10	%		0%		50	%
Long term government bond		5	%		0%		40	%
High yield bond		10	%		0%		25	%
Emerging markets bond		10	%		0%		20	%
Money market taxable		0	%		0%		100	%

Defined Benefit Plan, Fair Value of Plan Assets [Table Text Block]

	As of December 31, 2017
	Level 1		Level 2		Level 3		Total
Assets:
Insurance general account	$	-	$	16,873	$	-	$	16,873
Cash management accounts		3,229		-		-		3,229
Equity accounts		37,536		-		-		37,536
Fixed income accounts		27,146		-		-		27,146
Real estate accounts		3,464		-		-		3,464
Total	$	71,375	$	16,873	$	-	$	88,248

	As of December 31, 2016
	Level 1		Level 2		Level 3		Total
Assets:
Insurance general account	$	-	$	18,357	$	-	$	18,357
Cash management accounts		5,089		-		-		5,089
Equity accounts		31,963		-		-		31,963
Fixed income account		22,544		-		-		22,544
Real estate accounts		2,976		-		-		2,976
Total	$	62,572	$	18,357	$	-	$	80,929

Asset Categories [Member]

Notes Tables

Schedule of Allocation of Plan Assets [Table Text Block]

	As of December 31,
	2017			2016
Asset category:
Insurance general account		19	%		23	%
Cash management accounts		4	%		6	%
Equity accounts		42	%		39	%
Fixed income accounts		31	%		28	%
Real estate accounts		4	%		4	%
Total		100	%		100	%

Capital Accumulation Plan [Member]

Notes Tables

Defined Contribution Plan Disclosures [Table Text Block]

	Year Ended December 31,
	2017				2016				2015
	Shares		Amount		Shares		Amount		Shares		Amount
Matching contributions to the Capital Accumulation Plan		1,224	$	15		2,571	$	29		1,898	$	26