Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Comprehensive income attributable to common stockholders
Net income (loss)	$ 10,579	$ 4,235	$ (1,821)
Other comprehensive income:
Unrealized gain (loss) on available-for-sale securities	440	(191)	(100)
Benefit plan adjustments	135	(189)	404
Unrealized interest rate swap gains	(2,809)
Unrealized interest rate swap gains		988	970
Other comprehensive (loss) income before taxes	(2,658)	565	1,602
Benefit (provision) for income taxes related to other comprehensive income items	744	(158)	(627)
Other comprehensive (loss) income	(1,914)	407	975
Comprehensive income (loss)	8,665	4,642	(846)
Comprehensive loss attributable to non-controlling interests	(1)	(20)	(24)
Comprehensive income (loss) attributable to common stockholders	8,666	4,662	(822)
SERP
Other comprehensive income:
Benefit plan adjustments	$ (424)	$ (43)	$ 328