Non-controlling Interests (Components Of Non-controlling Interests) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Noncontrolling Interest [Line Items]
Non-controlling interests in consolidated subsidiaries	$ 4,332	$ 4,331
Australian Country Cinemas, Pty Ltd [Member]
Noncontrolling Interest [Line Items]
Non-controlling interests in consolidated subsidiaries	131	138
Shadow View Land And Farming, LLC [Member]
Noncontrolling Interest [Line Items]
Non-controlling interests in consolidated subsidiaries	2,142	2,127
Sutton Hill Properties, LLC [Member]
Noncontrolling Interest [Line Items]
Non-controlling interests in consolidated subsidiaries	$ 2,059	$ 2,066