Description Of Business And Segment Reporting (Reconciliation To Net Income Attributable To Common Shareholders) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Operating income (loss)	$ (17,375)	$ 2,840	$ (46,610)	$ 7,209
Depreciation and amortization expense	(5,612)	(5,704)	(16,149)	(16,870)
General and administrative expense	(4,228)	(5,908)	(15,275)	(18,426)
Equity earnings of unconsolidated joint ventures	(97)	220	(292)	581
Gain (loss) on sale of assets	(1)	(1)	(1)	(1)
Other income (expense)	10	141	(186)	190
Income (loss) before income taxes	(19,842)	1,329	(53,265)	2,055
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(14,254)	7,436	(34,782)	21,702
Unallocated Corporate Expense [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization expense	(215)	(103)	(634)	(288)
General and administrative expense	(2,906)	(4,493)	(11,194)	(14,205)
Interest expense, net	$ (2,379)	$ (1,871)	$ (6,176)	$ (5,924)