| Leases - Aggregate annual minimum cash to be received by the Company on the noncancelable operating leases (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Dec. 31, 2018 | 
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| Leases | ||
| 2019 (six months remaining) | $ 29,728 | $ 50,527 | 
| 2020 | 60,419 | 51,450 | 
| 2021 | 58,993 | 49,926 | 
| 2022 | 58,089 | 48,862 | 
| 2023 | 57,068 | 47,743 | 
| Thereafter | 374,196 | 330,180 | 
| Total | $ 638,493 | $ 578,688 | 
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- References No definition available. 
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- Definition Future minimum rental payments in aggregate as of the balance sheet date under operating leases. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Future rental payments receivable within the fifth year from the balance sheet date under an operating lease. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Future rental payments receivable within the fourth year from the balance sheet date under an operating lease. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Future rental payments receivable within the third year from the balance sheet date under an operating lease. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Future rental payments receivable within the second year from the balance sheet date under an operating lease. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of required minimum rental payments receivable in the remainder of the fiscal year following the latest fiscal year ended for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year. No definition available. 
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- Definition Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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