Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	$ 1,565
Interest rate swaps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	1,565
Interest rate caps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	0
Level 1
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	0
Level 1 | Interest rate swaps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	0
Level 1 | Interest rate caps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	0
Level 2
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	1,565
Level 2 | Interest rate swaps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	1,565
Level 2 | Interest rate caps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Total Financial Assets	$ 0