Fair-Value Measurements (Schedule of Fair Value of Financial Assets and Liabilities) (Details) - USD ($) $ in Thousands		Dec. 31, 2019		Dec. 31, 2018
Derivative asset:
Common stock of foreign public company, original cost		$ 500
Interest Rate Swap [Member]
Derivative liability:
Liability for fixed rate leg		15,200		$ 32,000
Receivable for floating rate leg		27,500		20,700
Quoted Prices in Active Markets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents		16,375		14,234
Common stock of foreign public company	[1]	839		731
Interest rate swaps
Liabilities:
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]
Liabilities:
Interest rate swaps		$ (5,518)	[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 $15.2 million receivable floating leg and $20.7 million liability fixed leg.