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Summary Of Significant Accounting Policies (Tables) | 12 Months Ended
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Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items] |
Property, Plant and Equipment [Table Text Block] | Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows:
Land improvements |  | 25 to 40 years
Buildings and improvements |  | 10 to 40 years
Tenant improvements |  | Shorter of useful life or terms of related lease
Furniture, fixtures, and equipment |  | 3 to 7 years
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] | The following table summarizes the scheduled amortization of the Company’s acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands).
|  | Acquired Above-Market Lease Intangibles |  | Acquired Below-Market Lease Intangibles
2019 |  | $ | 7,099 |  |  | $ | 27,327 |
2020 |  | 5,394 |  |  | 10,462 |
2021 |  | 2,988 |  |  | 6,348 |
2022 |  | 314 |  |  | 5,669 |
2023 |  | 168 |  |  | 5,558 |
The following table summarizes the scheduled amortization of the Company’s acquired in-place lease intangibles for each of the five succeeding years (in thousands).
| Acquired In-Place Lease Intangibles
2019 | $ | 25,690 |
2020 | 13,051 |
2021 | 8,610 |
2022 | 4,798 |
2023 | 4,107 |
Schedule Of Future Contractual Minimum Lease Payments Under Non-Cancelable Ground Leases [Table Text Block] | The future contractual minimum lease payments to be made by the Company as of December 31, 2018, under non-cancelable ground leases which expire on various dates through 2114, are as follows:
Years Ending December 31, | (in thousands)
2019 | $ | 11,425 |
2020 | 18,425 |
2021 | 25,310 |
2022 | 8,894 |
2023 | 9,084 |
Thereafter | 567,232 |
Capital Leases in Financial Statements of Lessee Disclosure [Text Block] | Capital Leases The Company has four capital lease obligations with various initial term expiration dates through 2036. The following reflects the gross amount of assets recorded under capital leases by asset class at December 31, 2018 and December 31, 2017 (in thousands):
|  | December 31,
|  | 2018 |  | 2017
Land held for future development |  | $ | 12,397 |  |  | $ | — |
Buildings and improvements |  | 23,636 |  |  | 23,636 |
Construction in progress |  | 28,962 |  |  | 28,962 |
Total |  | $ | 64,995 |  |  | $ | 52,598 |
The future minimum lease payments, as of December 31, 2018, related to the four capital leases, through 2036 are as follows:
Years Ending December 31, | (in thousands)
2019 | $ | 1,441 |
2020 | 12,682 |
2021 | 2,123 |
2022 | 1,253 |
2023 | 944 |
Thereafter | 73,241 |
Total expected minimum lease payments | 91,684 |
Interest portion | (27,497 | )
Present value of expected net minimum lease payments | $ | 64,187 |
Fair Value, by Balance Sheet Grouping [Table Text Block] | The following table presents the aggregate carrying value of the Company’s related party note receivable, note receivable, mortgage notes payable, net, unsecured senior notes, net, unsecured line of credit and unsecured term loan, net and the Company’s corresponding estimate of fair value as of December 31, 2018 and December 31, 2017 (in thousands):
| December 31, 2018 |  | December 31, 2017
| Carrying Amount |  | Estimated Fair Value |  | Carrying Amount |  | Estimated Fair Value
Related party note receivable | $ | 80,000 |  |  | $ | 80,000 |  |  | $ | — |  |  | $ | — |
Note receivable | 19,468 |  |  | 19,468 |  |  | — |  |  | — |
Total | $ | 99,468 |  |  | $ | 99,468 |  |  | $ | — |  |  | $ | — |
Mortgage notes payable, net | $ | 2,964,572 |  |  | $ | 2,903,925 |  |  | $ | 2,979,281 |  |  | $ | 3,042,920 |
Unsecured senior notes, net | 7,544,697 |  |  | 7,469,338 |  |  | 7,247,330 |  |  | 7,461,615 |
Unsecured line of credit | — |  |  | — |  |  | 45,000 |  |  | 45,000 |
Unsecured term loan, net | 498,488 |  |  | 500,783 |  |  | — |  |  | — |
Total | $ | 11,007,757 |  |  | $ | 10,874,046 |  |  | $ | 10,271,611 |  |  | $ | 10,549,535 |
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes, Table [Table Text Block] | The tax treatment of common dividends per share for federal income tax purposes is as follows:
|  | For the year ended December 31,
|  | 2018 |  | 2017 |  | 2016
|  | Per Share |  | % |  | Per Share |  | % |  | Per Share |  | %
Ordinary income |  | $ | 2.79 |  |  | 78.17 | % |  | $ | 2.86 |  |  | 98.29 | % |  | $ | 2.76 |  |  | 90.51 | %
Capital gain income |  | 0.78 |  |  | 21.83 | % |  | 0.05 |  |  | 1.71 | % |  | 0.29 |  |  | 9.49 | %
Total |  | $ | 3.57 |  | (1) | 100.00 | % |  | $ | 2.91 |  | (2) | 100.00 | % |  | $ | 3.05 |  | (3) | 100.00 | %
_____________
(1) | The fourth quarter 2018 regular quarterly dividend was $0.95 per common share of which approximately $0.69 per common share was allocable to 2018 and approximately $0.26 per common share is allocable to 2019.
(2) | The fourth quarter 2017 regular quarterly dividend was $0.80 per common share of which approximately $0.47 per common share was allocable to 2017 and approximately $0.33 per common share is allocable to 2018.
(3) | The fourth quarter 2016 regular quarterly dividend was $0.75 per common share of which approximately $0.56 per common share was allocable to 2016 and approximately $0.19 per common share is allocable to 2017.

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- Definition The entire disclosure for capital leasing arrangements including, but not limited to, the following: a) the basis on which contingent rental payments are determined; (b) the existence and terms of renewal or purchase options and escalation clauses; (c) restrictions imposed by lease agreements, such as those concerning dividends, additional debt, and further leasing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -URI http://asc.fasb.org/subtopic&trid=2209026 + Details
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- Definition Tabular disclosure of the fair value of financial instruments, including financial assets and financial liabilities, and the measurements of those instruments, assets, and liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13476-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13467-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=75026489&loc=d3e13220-108610 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 30 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14172-108612 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 + Details
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