Lease Agreements - Company as Lessor (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($) building	Dec. 31, 2018 USD ($) building
Lessor, Lease, Description [Line Items]
Number of commercial buildings under lease agreements | building	1	1
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
Remaining in 2019	$ 511,596
2020	232,775
2021	14,872
2022	13,650
2023	12,614
Thereafter	34,218
Operating leases	$ 819,725
Operating Leases, Future Minimum Payments Receivable [Abstract]
2019		$ 16,386
2020		15,842
2021		14,412
2022		13,324
2023		12,181
Thereafter		33,034
Future minimum receivables		$ 105,179
Minimum
Lessor, Lease, Description [Line Items]
Short-term lease terms	9 months
Commercial lease terms	5 years
Maximum
Lessor, Lease, Description [Line Items]
Short-term lease terms	12 months
Commercial lease terms	20 years