Quarterly Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 210,421	$ 207,598	$ 204,776	$ 202,321	$ 181,089	$ 187,652	$ 183,148	$ 180,127	$ 825,116	$ 723,942	$ 654,420
Income (Loss) from Continuing Operations before Interest Expense, Interest Income, Income Taxes, Noncontrolling Interests, Net	(5,260)	(36,074)	(3,605)	12,333	(19,416)	(15,870)	19,332	11,716
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(8,051)	(28,215)	(2,797)	9,578	(10,968)	(11,707)	14,701	8,369	(29,485)	394	10,145
Net Income (Loss) Attributable to Noncontrolling Interest	107	65	106	109	103	1	0	0	387	104	0
Net Income (Loss) Attributable to Parent	$ (8,158)	$ (28,280)	$ (2,903)	$ 9,469	$ (11,071)	$ (11,708)	$ 14,701	$ 8,369	$ (29,872)	$ 290	$ 10,145
Earnings Per Share, Basic	$ (0.19)	$ (0.66)	$ (0.07)	$ 0.22	$ (0.26)	$ (0.27)	$ 0.34	$ 0.20	$ (0.70)	$ 0.01	$ 0.27
Earnings Per Share, Diluted	$ (0.19)	$ (0.66)	$ (0.07)	$ 0.22	$ (0.26)	$ (0.27)	$ 0.34	$ 0.20	$ (0.70)	$ 0.01	$ 0.27