Lease Agreements - Company as Lessor (Details) $ in Thousands	3 Months Ended
	Mar. 31, 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	$ 612,190
2020	64,761
2021	14,599
2022	13,397
2023	12,403
Thereafter	33,304
Operating leases	$ 750,654
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