Stock Compensation Plans (Summary of Vesting Date Fair Value of Awards) (Details 9) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Performance-based Operational Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting date fair value of Performance-Based Operational and TSR Awards	$ 2,861	$ 0	$ 2,541
Performance Based TSR Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting date fair value of Performance-Based Operational and TSR Awards	$ 300	$ 0	$ 0

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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

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