STATEMENTS OF CHANGES IN MEMBERS' EQUITY - USD ($) $ in Thousands	Accumulated Other Comprehensive Income [Member]	Members Equity [Member]	Total
BALANCE at Dec. 31, 2013		$ 38,416	$ 38,416
Increase (Decrease) in Stockholders' Equity
Net income		5,242	5,242
Member distributions		(9,605)	(9,605)
BALANCE at Dec. 31, 2014		34,053	34,053
Increase (Decrease) in Stockholders' Equity
Net income		4,533	4,533
Member distributions		(10,225)	(10,225)
Pension liability adjustment	$ (48)		(48)
BALANCE at Dec. 31, 2015	(48)	28,361	28,313
Increase (Decrease) in Stockholders' Equity
Net income		4,704	4,704
Member distributions		(9,449)	(9,449)
Pension liability adjustment	$ 48		48
BALANCE at Dec. 31, 2016		$ 23,616	$ 23,616