Debt Interest Rate Swaps 3 (Details) - Forward-starting Interest Rate Swap 1 [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Derivative, Forward-starting Effective Date	Nov. 20, 2019
Derivative, Forward Starting Maturity Date	Nov. 20, 2020
Derivative, Forward Starting Notional Amount	$ 150.0
Derivative, Forward-starting interest rate swap agreement, fixed interest rate	1.1425%
Derivative, Forward Starting Swap Inception Date	Jul. 06, 2016