Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Future Minimum Rental Payments Due under Terms of Leases (Detail)

v3.3.1.900
Commitments and Contingencies - Future Minimum Rental Payments Due under Terms of Leases (Detail)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
USD ($)
Operating Leased Assets [Line Items]  
For the year ended December 31, 2017 $ 79,913
For the year ended December 31, 2018 79,638
For the year ended December 31, 2019 79,494
For the year ended December 31, 2020 72,333
Ground Leases [Member]  
Operating Leased Assets [Line Items]  
For the year ended December 31, 2016 459
For the year ended December 31, 2017 462
For the year ended December 31, 2018 465
For the year ended December 31, 2019 465
For the year ended December 31, 2020 466
Thereafter $ 4,948
Ground Leases [Member] | Tulsa, OK [Member]  
Operating Leased Assets [Line Items]  
Lease End Date 2021-04
For the year ended December 31, 2016 $ 169
For the year ended December 31, 2017 169
For the year ended December 31, 2018 169
For the year ended December 31, 2019 169
For the year ended December 31, 2020 169
Thereafter $ 85
Ground Leases [Member] | Dartmouth, MA [Member]  
Operating Leased Assets [Line Items]  
Lease End Date 2036-05
For the year ended December 31, 2016 $ 174
For the year ended December 31, 2017 174
For the year ended December 31, 2018 174
For the year ended December 31, 2019 174
For the year ended December 31, 2020 174
Thereafter $ 3,126
Ground Leases [Member] | Springfield, MA [Member]  
Operating Leased Assets [Line Items]  
Lease End Date 2030-02
For the year ended December 31, 2016 $ 86
For the year ended December 31, 2017 89
For the year ended December 31, 2018 90
For the year ended December 31, 2019 90
For the year ended December 31, 2020 90
Thereafter $ 884
Ground Leases [Member] | Salt Lake City, UT [Member]  
Operating Leased Assets [Line Items]  
Lease End Date 2040-11
For the year ended December 31, 2016 $ 30
For the year ended December 31, 2017 30
For the year ended December 31, 2018 32
For the year ended December 31, 2019 32
For the year ended December 31, 2020 33
Thereafter $ 853