Debt and Derivative Instruments (Summary of Interest Rate Swap Contracts Outstanding) (Parenthetical) (Details)	3 Months Ended
Mar. 31, 2017
Derivative [Line Items]
Derivative instrument, receive floating rate index	1 month LIBOR
LIBOR [Member]
Derivative [Line Items]
One month floating rate	0.98%

When the derivative or group of derivatives presented is a swap, the type of interest rate (fixed, variable, stepped, etc.) paid on the swap.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column A
-Footnote 1

Name:	invest_DerivativeTypeOfInterestRatePaidOnSwap
Namespace Prefix:	invest_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration