Share-Based Compensation (Schedule Of Performance Vesting Restricted Stock Units Granted) (Details) - shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Three-year performance period ending December 31,	2018	2017
Vesting shares, target	90,750	93,750
Vesting shares, maximum	170,156	175,781

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration