Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	[1]	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income attributable to RDI common stockholders	$ 4,960		$ 1,297	$ 5,027	$ 3,082	$ 7,426		$ 1,576	$ 19,051	$ 3,048	$ 14,366	$ 31,101	$ 9,678	[2]
Weighted average number of common stock – basic											22,991,277	23,041,190	23,320,048	[2]
Weighted average dilutive impact of stock-based awards											217,714	206,779	201,109
Weighted average shares of common stock – diluted											23,208,991	23,247,969	23,521,157	[2]
Basic EPS attributable to RDI common stockholders	$ 0.21		$ 0.06	$ 0.22	$ 0.13	$ 0.33		$ 0.07	$ 0.82	$ 0.13	$ 0.62	$ 1.35	$ 0.42	[2]
Diluted EPS attributable to RDI common stockholders	$ 0.21		$ 0.06	$ 0.22	$ 0.13	$ 0.32		$ 0.07	$ 0.81	$ 0.13	$ 0.62	$ 1.34	$ 0.41	[2]
Awards excluded from diluted EPS											276,681	149,841	92,500

[1] Net income for the 4th quarter of 2017 includes approximately $2.5 million net tax benefit from non-recurring items of tax benefit and expense related to the Tax Cuts and Jobs Act enacted December 2017 and dissolution of a non-operating foreign subsidiary.

[2] Certain prior year balances have been reclassified to conform to the 2017 presentation (see Note 2 - Summary of Significant Accounting Policies - Reclassifications).