Fair-Value Measurements (Schedule of Fair Value of Financial Assets and Liabilities) (Details) - USD ($) $ in Thousands		Dec. 31, 2018		Dec. 31, 2017
Liabilities:
Interest rate swaps		$ (9,025)
Derivative asset:
Common stock of foreign public company, original cost		500
Interest Rate Swap [Member]
Derivative liability:
Liability for fixed rate leg		32,000		$ 34,900
Receivable for floating rate leg		27,500		34,600
Quoted Prices in Active Markets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents		14,234		13,601
Common stock of foreign public company	[1]	731		999
Interest rate swaps
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents
Common stock of foreign public company	[1]
Interest rate swaps		$ 4,548	[2]	$ 313	[3]

[1] Original cost basis $0.5 million.

[2] Net of $32.0 million receivable floating leg and $27.5 million liability fixed leg

[3] Net of $34.9 million receivable floating leg and $34.6 million liability fixed leg