Earnings Per Share (Computation Of Basic And Diluted Earnings (Loss) Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income (loss) attributable to RDI common stockholders	$ 18,965	$ (5,875)
Weighted average number of common stock – basic	21,761,307	21,752,371
Weighted average dilutive impact of awards	408,961	367,250
Weighted average number of common stock – diluted	22,170,268	22,119,621
Basic earnings (loss) per share attributable to RDI common stockholders	$ 0.87	$ (0.27)
Diluted earnings (loss) per share attributable to RDI common stockholders	$ 0.86	$ (0.27)
Awards excluded from diluted earnings (loss) per share	514,341	678,377