Fair Value Disclosure (On a Recurring Basis) (Details) - Fair value measurements, recurring - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Level 1
Assets:
Available for sale securities	$ 8,595	$ 7,882	$ 7,498
Interest rate swap agreements	0	0
Foreign currency exchange contracts		0
Assets at fair value	8,595	7,882	7,498
Liabilities:
Interest rate swap agreements	0	0	0
Foreign currency exchange contracts	0		0
Liabilities at fair value	0	0	0
Level 2
Assets:
Available for sale securities	0	0	0
Interest rate swap agreements	623	774
Foreign currency exchange contracts		147
Assets at fair value	623	921	0
Liabilities:
Interest rate swap agreements	29	339	2,491
Foreign currency exchange contracts	903		295
Liabilities at fair value	932	339	2,786
Level 3
Assets:
Available for sale securities	0	0	0
Interest rate swap agreements	0	0
Foreign currency exchange contracts		0
Assets at fair value	0	0	0
Liabilities:
Interest rate swap agreements	0	0	0
Foreign currency exchange contracts	0		0
Liabilities at fair value	0	0	0
Total
Assets:
Available for sale securities	8,595	7,882	7,498
Interest rate swap agreements	623	774
Foreign currency exchange contracts		147
Assets at fair value	9,218	8,803	7,498
Liabilities:
Interest rate swap agreements	29	339	2,491
Foreign currency exchange contracts	903		295
Liabilities at fair value	$ 932	$ 339	$ 2,786