Right-of-Use Assets and Operating Lease Liabilities (Lease Information) (Details) $ in Thousands	Mar. 31, 2019 USD ($) lease
Lessee, Lease, Description [Line Items]
Number of ground leases | lease	3
Ground Leases
Lessee, Lease, Description [Line Items]
Operating lease – ROU assets	$ 4,190
Operating lease – lease liabilities	$ (5,898)
Weighted average remaining lease term	15 years 2 months 12 days
Weighted average discount rate	4.10%
Operating lease - accrued lease payments	$ 1,708
Headquarters Office Lease
Lessee, Lease, Description [Line Items]
Operating lease – ROU assets	3,367
Operating lease – lease liabilities	$ (4,063)
Weighted average remaining lease term	6 years
Weighted average discount rate	3.50%
Operating lease - accrued lease payments	$ 696