Leases - Leases under ASC 840 (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Leases [Abstract]
Gross Rents, 2018	$ 20,776
Gross Rents, 2019	27,570
Gross Rents, 2020	27,709
Gross Rents, 2021	26,872
Gross Rents, 2022	25,860
Gross Rents, Thereafter	270,431
Gross Rents, Total Lease Payments	399,218
Sublease Income, 2018	1,644
Sublease Income, 2019	2,124
Sublease Income, 2020	2,077
Sublease Income, 2021	2,009
Sublease Income, 2022	1,891
Sublease Income, Thereafter	8,130
Sublease Income, Total Lease Payments	17,875
Net Rents, 2018	19,132
Net Rents, 2019	25,446
Net Rents, 2020	25,632
Net Rents, 2021	24,863
Net Rents, 2022	23,969
Net Rents, Thereafter	262,301
Net Rents, Total Lease Payments	$ 381,343