Savings and Retirement Plans (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Savings and Retirement Plans [Abstract]
Employer discretionary contribution amount to U.S. plan	$ 221,000	$ 123,000
Defined Benefit Plans, Net Periodic Retirement Cost [Abstract]
Gross service cost	21,000	26,000
Interest cost	23,000	29,000
Management cost	3,000	1,000
Expected return on assets	(21,000)	(24,000)
Amortization	0	(1,000)
Net periodic retirement cost	$ 26,000	$ 31,000