Derivative Instruments (Textual) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments [Abstract]
Derivative Cash Received On Hedge	$ (8,055)	$ 8,218

The amount of cash received during the period on settlement of a hedge.

No definition available.

Name:	us-gaap_DerivativeCashReceivedOnHedge
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration