Noncontrolling Interest in Operating Partnership - Schedule of OP Unit Activity (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Noncontrolling Interest [Abstract]
OP Units redeemed for common stock (in units)	25,000	0
OP Units redeemed for cash (in units)	30,000	33,896
Cash paid for OP Units redeemed	$ 2,558	$ 2,510
OP Units issued in conjunction with acquisitions (in units)	21,768	25,520
Value of OP Units issued in conjunction with acquisitions	$ 1,877	$ 2,000