Fair Value Disclosure (On a Recurring Basis) (Details) - Fair value measurements, recurring - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Level 1
Assets:
Available for sale securities	$ 8,229	$ 7,882	$ 7,347
Interest rate swap agreements	0	0
Foreign currency exchange contracts	0	0
Assets at fair value	8,229	7,882	7,347
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	802	774
Foreign currency exchange contracts	27	147
Assets at fair value	829	921	0
Liabilities:
Interest rate swap agreements	103	339	1,850
Foreign currency exchange contracts	489		491
Liabilities at fair value	592	339	2,341
Level 3
Assets:
Available for sale securities	0	0	0
Interest rate swap agreements	0	0
Foreign currency exchange contracts	0	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	8,229	7,882	7,347
Interest rate swap agreements	802	774
Foreign currency exchange contracts	27	147
Assets at fair value	9,058	8,803	7,347
Liabilities:
Interest rate swap agreements	103	339	1,850
Foreign currency exchange contracts	489		491
Liabilities at fair value	$ 592	$ 339	$ 2,341