CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Class B Common Stock	Total Stockholders' Equity	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Treasury Stock	Accumulated Other Comprehensive Loss	Additional Paid-in Capital	Retained Earnings (Deficit)	Non-controlling Interest
Balance at beginning of period (in shares) at Dec. 31, 2018				14,178	20,800	(99)
Balance at beginning of period at Dec. 31, 2018	$ 90,294		$ 45,806	$ 142	$ 209	$ (2,011)	$ 2	$ 46,157	$ 1,307	$ 44,488
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock unit vesting (in shares)				63
Restricted stock unit vesting	1,071		1,071					1,071
Consolidated net income	2,745		782						782	1,963
Impact of adoption of ASC 606	(35)		(14)				(14)			(21)
Distributions paid to non-controlling unit holders	(3,770)									(3,770)
Dividends paid to Class A common stockholders ($0.18125 per share)	(2,564)		(2,564)					(2,564)
Changes in ownership interest	0		1,059					1,059		(1,059)
Dividends paid to Preferred Stockholders	(2,027)		(2,027)						(2,027)
Proceeds from disgorgement of stockholder short-swing profits	46		46					46
Acquisition of Customers from Affiliate	(10)									(10)
Balance at end of period (in shares) at Mar. 31, 2019				14,241	20,800	99
Balance at end of period at Mar. 31, 2019	85,750		44,159	$ 142	$ 209	$ (2,011)	(12)	45,769	62	41,591
Balance at beginning of period (in shares) at Dec. 31, 2019				14,479	20,800	99
Balance at beginning of period at Dec. 31, 2019	67,286		51,219	$ 145	$ 209	$ (2,011)	(40)	51,842	1,074	16,067
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation	1,329		1,329					1,329
Restricted stock unit vesting (in shares)				16
Restricted stock unit vesting	(39)		(39)					(39)
Consolidated net income	10,068		4,479						4,479	5,589
Impact of adoption of ASC 606	0
Distributions paid to non-controlling unit holders	(7,172)	$ (3,800)								(7,172)
Dividends paid to Class A common stockholders ($0.18125 per share)	(2,606)		(2,606)						(2,606)
Changes in ownership interest	0		(422)					(422)		422
Dividends paid to Preferred Stockholders	(1,500)		(1,500)						(1,500)
Balance at end of period (in shares) at Mar. 31, 2020				14,495	20,800	99
Balance at end of period at Mar. 31, 2020	$ 66,733		$ 51,827	$ 145	$ 209	$ (2,011)	$ (40)	$ 52,710	$ 814	$ 14,906