Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2017

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Schedule of Defined Benefit Plans Disclosures

The following tables provide the components of net periodic benefit costs for the three and six-month periods ended June 30, 2017 and 2016.

				Select
	Employees'			Executive		Postretirement
	Pension			Retirement		Benefit
	Plan			Plan		Plans
Net Periodic Benefit Cost
For the Three Months Ended June 30, 2017:
Service Cost	$	350		$	10	$	37
Interest Cost	373			59		63
Expected Return on Plan Assets	(800		)	—		—
Amortization of Prior Service (Credit) Cost	(14		)	14		(3		)
Amortization of Net Loss	148			33		—
Net Periodic Benefit Cost	$	57		$	116	$	97
Plan Contributions During the Period	$	—		$	116	$	177
For the Three Months Ended June 30, 2016:
Service Cost	$	376		$	8	$	63
Interest Cost	424			48		15
Expected Return on Plan Assets	(828		)	—		—
Amortization of Prior Service (Credit) Cost	(15		)	14		(3		)
Amortization of Net Loss	138			28		—
Net Periodic Benefit Cost	$	95		$	98	$	75
Plan Contributions During the Period	$	—		$	112	$	72
Net Periodic Benefit Cost
For the Six Months Ended June 30, 2017:
Service Cost	$	700		$	20	$	74
Interest Cost	723			109		149
Expected Return on Plan Assets	(1,600		)	—		—
Amortization of Prior Service Cost (Credit)	(28		)	28		(6		)
Amortization of Net Loss	296			63		—
Net Periodic Benefit Cost	$	91		$	220	$	217
Plan Contributions During the Period	$	—		$	229	$	230
Estimated Future Contributions in the Current Fiscal Year	$	—		$	229	$	230
For the Six Months Ended June 30, 2016:
Service Cost	$	752		$	16	$	125
Interest Cost	844			106		96
Expected Return on Plan Assets	(1,656		)	—		—
Amortization of Prior Service (Credit) Cost	(30		)	29		(6		)
Amortization of Net Loss	278			56		—
Net Periodic Benefit Cost	$	188		$	207	$	215
Plan Contributions During the Period	$	—		$	219	$	150