Fair Value of Derivative and Financial Instruments - Outstanding Interest Rate Derivatives Not Designated as Cash Flow Hedges of Interest Rate Risk (Details) - Not designated as hedging instrument - Interest rate caps	Mar. 31, 2019 USD ($) DerivativeInstrument	Mar. 31, 2018 USD ($) DerivativeInstrument
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Number of Instruments | DerivativeInstrument	13	11
Derivative notional amount | $	$ 310,028,000	$ 177,300,000