Fair-Value Measurements (Schedule of Fair Value of Financial Assets and Liabilities) (Details) - USD ($) $ in Thousands		Mar. 31, 2017		Dec. 31, 2016
Derivative asset:
Common stock of foreign public company, original cost		$ 500		$ 500
Interest Rate Current Swap [Member]
Derivative asset:
Liability for fixed rate leg		21,300		21,400
Receivable for floating rate leg		14,700		15,600
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Assets:
Cash equivalents		8,146		8,468
Foreign currency options		77
Common stock of unaffiliated foreign public company	[1]	811		762
Liabilities:
Interest rate swaps
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Cash equivalents
Foreign currency options
Common stock of unaffiliated foreign public company	[2]
Liabilities:
Interest rate swaps		$ 6,588	[3]	$ 5,784	[2]

[1] Original cost basis $0.5 million.

[2] Net of $21.4 million receivable floating leg and $15.6 million liability fixed leg.

[3] Net of $21.3 million receivable floating leg and $14.7 million liability fixed leg