Fair Value Disclosure (Schedule of Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets:
Available for sale securities	$ 7,882	$ 7,247
Interest rate swap agreements	774	3
Foreign currency exchange contracts	147	386
Assets	8,803	7,636
Liabilities:
Interest rate swap agreements	339	698
Liabilities	339	698
Quoted prices in active markets for identical assets (level 1)
Assets:
Available for sale securities	7,882	7,247
Interest rate swap agreements	0	0
Foreign currency exchange contracts	0	0
Assets	7,882	7,247
Liabilities:
Interest rate swap agreements	0	0
Liabilities	0	0
Significant other observable inputs (level 2)
Assets:
Available for sale securities	0	0
Interest rate swap agreements	774	3
Foreign currency exchange contracts	147	386
Assets	921	389
Liabilities:
Interest rate swap agreements	339	698
Liabilities	339	698
Significant unobservable inputs (level 3)
Assets:
Available for sale securities	0	0
Interest rate swap agreements	0	0
Foreign currency exchange contracts	0	0
Assets	0	0
Liabilities:
Interest rate swap agreements	0	0
Liabilities	$ 0	$ 0