Retirement Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension expense	$ (2)	$ 45
Supplemental Employee Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension expense	$ 202	$ 148
Supplemental Employee Retirement Plan \| Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Retirement benefit percentage	10.00%
Supplemental Employee Retirement Plan \| Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Retirement benefit percentage	20.00%

The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration