Derivative and Other Fair Value Instruments - Summary of Consolidated Derivative Instruments (Details)	6 Months Ended
	Jun. 30, 2017 USD ($)
Fair Value Hedges [Member]
Derivative [Line Items]
Current Notional Balance	$ 450,000,000
Earliest Maturity Date	2019
Latest Maturity Date	2019
Fair Value Hedges [Member] | Lowest [Member]
Derivative [Line Items]
Interest Rate	2.375%
Fair Value Hedges [Member] | Highest [Member]
Derivative [Line Items]
Interest Rate	2.375%
Forward Starting Swaps [Member]
Derivative [Line Items]
Current Notional Balance	$ 300,000,000
Earliest Maturity Date	2027
Latest Maturity Date	2028
Forward Starting Swaps [Member] | Lowest [Member]
Derivative [Line Items]
Interest Rate	2.163%
Forward Starting Swaps [Member] | Highest [Member]
Derivative [Line Items]
Interest Rate	2.2895%