Derivative Instruments	6 Months Ended
Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments Interest Rate Derivatives—We are exposed to risks arising from our business operations, economic conditions and financial markets. To manage these risks, we primarily use interest rate derivatives to hedge our debt and our cash flows. The interest rate derivatives include interest rate caps and interest rate floors, which are subject to master netting settlement arrangements. All derivatives are recorded at fair value. During the six months ended June 30, 2017, we entered into interest rate caps with notional amounts totaling $619.5 million and strike rates ranging from 3.00% to 5.35%. These interest rate caps have effective dates from January 2017 to May 2017, maturity dates from March 2018 to May 2019, and a total cost of $338,000. These instruments were not designated as cash flow hedges. During the six months ended June 30, 2016, concurrent with the extension of our $80.0 million mortgage loan, we extended our existing interest rate cap with a notional amount of $80.0 million, maturity date of March 2017 and a strike rate of 5.78% for a total cost of $5,000. This instrument was not designated as a cash flow hedge. As of June 30, 2017, we held interest rate caps with notional amounts totaling $847.5 million and strike rates ranging from 2.00% to 5.43%. These instruments cap the interest rates on our mortgage loans with an aggregate principal balance of $906.9 million and maturity dates from December 2017 to May 2022. These instruments have maturity dates ranging from December 2017 to May 2019. As of June 30, 2017, we held interest rate floors with notional amounts totaling $3.0 billion and a strike rate of -0.25% and a maturity date of July 2020. Options on Futures Contracts—During the six months ended June 30, 2016, we purchased options on Eurodollar futures for a total cost of $124,000 and a maturity date of June 2017. During the six months ended June 30, 2017, we made no such purchases.

Derivative Instruments

Interest Rate Derivatives—We are exposed to risks arising from our business operations, economic conditions and financial markets. To manage these risks, we primarily use interest rate derivatives to hedge our debt and our cash flows. The interest rate derivatives include interest rate caps and interest rate floors, which are subject to master netting settlement arrangements. All derivatives are recorded at fair value.

During the six months ended June 30, 2017, we entered into interest rate caps with notional amounts totaling $619.5 million and strike rates ranging from 3.00% to 5.35%. These interest rate caps have effective dates from January 2017 to May 2017, maturity dates from March 2018 to May 2019, and a total cost of $338,000. These instruments were not designated as cash flow hedges.

During the six months ended June 30, 2016, concurrent with the extension of our $80.0 million mortgage loan, we extended our existing interest rate cap with a notional amount of $80.0 million, maturity date of March 2017 and a strike rate of 5.78% for a total cost of $5,000. This instrument was not designated as a cash flow hedge.

As of June 30, 2017, we held interest rate caps with notional amounts totaling $847.5 million and strike rates ranging from 2.00% to 5.43%. These instruments cap the interest rates on our mortgage loans with an aggregate principal balance of $906.9 million and maturity dates from December 2017 to May 2022. These instruments have maturity dates ranging from December 2017 to May 2019. As of June 30, 2017, we held interest rate floors with notional amounts totaling $3.0 billion and a strike rate of -0.25% and a maturity date of July 2020.

Options on Futures Contracts—During the six months ended June 30, 2016, we purchased options on Eurodollar futures for a total cost of $124,000 and a maturity date of June 2017. During the six months ended June 30, 2017, we made no such purchases.