Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value (Details) - Fair Value Measurements Recurring $ in Thousands	Jun. 30, 2018 USD ($)
Level 1
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	$ 0
Level 1 | Interest rate swaps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	0
Derivative liabilities	0
Level 1 | Interest rate cap
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	0
Level 2
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	3,478
Level 2 | Interest rate swaps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	3,473
Derivative liabilities	0
Level 2 | Interest rate cap
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	5
Carrying and Fair Value
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	3,478
Carrying and Fair Value | Interest rate swaps
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	3,473
Derivative liabilities	0
Carrying and Fair Value | Interest rate cap
Financial Instruments Measured at Fair Value: Available-for-sale securities - (Corporate equity securities)
Derivative assets	$ 5