Income Taxes	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The difference between the statutory tax rate and the Company's effective tax rates for the three and nine months ended September 30, 2018 and September 30, 2017 reflects a decrease in the Company's federal statutory tax rate from 35% to 21% as a result of the Tax Act and a decrease in the valuation allowance recorded in 2018 as compared to 2017. These decreases were offset by the elimination of deductibility for qualified performance-based compensation of covered employees in 2018 as a result of the Tax Act, the negative tax benefit on the vesting of restricted stock, a direct result of the Company's lower stock price in 2018, and the non-deductible write-off of goodwill. The valuation allowance during the three and nine months ended September 30, 2018 reflects a reduction in the allowance of $2.7 million and an additional allowance of $52.2 million, respectively, established against the current period operating loss and is reflective of the Company's quarterly calculation of the reversal of existing tax assets and liabilities and the impact of the Company's acquisitions, dispositions, and other significant transactions, including the impact of the Tax Act which allows for the unlimited carryover of net operating losses created in 2018 and beyond. The increase in the valuation allowance during the nine months ended September 30, 2017 was comprised of multiple components. The increase included $85.0 million related to the removal of future timing differences as a result of the formation of the Blackstone Venture and termination of leases associated therewith. In addition, the Company increased its valuation allowance by $48.5 million upon the adoption of ASU 2016-09, Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting. The $48.5 million offset the increase to the Company's net operating loss carryforward position previously reflected in an additional paid-in capital pool, and accordingly, did not impact the current period income tax position. The remaining change of approximately $86.6 million for the nine months ended September 30, 2017 reflects the allowance established against that period's operating loss. The Company recorded an aggregate deferred federal, state and local tax benefit of $15.4 million and $71.3 million as a result of the operating loss for the three and nine months ended September 30, 2018, respectively. The benefit for the three months ended September 30, 2018 includes a benefit from a decrease in the valuation allowance of $2.7 million. The benefit for the nine months ended September 30, 2018 was offset by an increase in the valuation allowance of $52.2 million. The change in the valuation allowance for the three and nine months ended September 30, 2018 is the result of the anticipated reversal of future tax liabilities offset by future tax deductions. The Company recorded an aggregate deferred federal, state, and local tax benefit of $91.3 million and $123.0 million as a result of the operating loss for the three and nine months ended September 30, 2017, respectively, which was offset by an increase in the valuation allowance of $59.6 million and $86.6 million, respectively. The Company evaluates its deferred tax assets each quarter to determine if a valuation allowance is required based on whether it is more likely than not that some portion of the deferred tax asset would not be realized. The Company's valuation allowance as of September 30, 2018 and December 31, 2017 is $388.3 million and $336.1 million, respectively. For the year ended December 31, 2017, the Company estimated the impact of the Tax Act on state income taxes reflected in its income tax benefit. Reasonable estimates for the Company's state and local provision continue to be made based on the Company's analysis of tax reform. These provisional amounts have not been adjusted for the three and nine months ended September 30, 2018 but may be adjusted in future periods during 2018 when additional information is obtained. In addition, the Tax Act limits the annual deductibility of a corporation's net interest expense unless it elects to be exempt from such deductibility limitation under the real property trade or business exception. The Company plans to elect the real property trade or business exception with the 2018 tax return. As such, the Company will be required to apply the alternative depreciation system ("ADS") to all current and future residential real property and qualified improvement property assets. This change did not have a material effect for the three and nine months ended September 30, 2018 but will impact future tax depreciation deductions and may impact the Company's valuation allowance. The Company is unable to estimate the future impact of this change at this time. Additional information that may affect the Company's provisional amounts would include further clarification and guidance on how the Internal Revenue Service will implement tax reform and further clarification and guidance on how state taxing authorities will implement tax reform and the related effect on the Company's state and local income tax returns, state and local net operating losses and corresponding valuation allowances. The Company recorded interest charges related to its tax contingency reserve for cash tax positions for the three and nine months ended September 30, 2018 and September 30, 2017 which are included in income tax expense or benefit for the period. As of September 30, 2018, tax returns for years 2013 through 2017 are subject to future examination by tax authorities. In addition, the net operating losses from prior years are subject to adjustment under examination.

Income Taxes

The difference between the statutory tax rate and the Company's effective tax rates for the three and nine months ended September 30, 2018 and September 30, 2017 reflects a decrease in the Company's federal statutory tax rate from 35% to 21% as a result of the Tax Act and a decrease in the valuation allowance recorded in 2018 as compared to 2017. These decreases were offset by the elimination of deductibility for qualified performance-based compensation of covered employees in 2018 as a result of the Tax Act, the negative tax benefit on the vesting of restricted stock, a direct result of the Company's lower stock price in 2018, and the non-deductible write-off of goodwill.

The valuation allowance during the three and nine months ended September 30, 2018 reflects a reduction in the allowance of $2.7 million and an additional allowance of $52.2 million, respectively, established against the current period operating loss and is reflective of the Company's quarterly calculation of the reversal of existing tax assets and liabilities and the impact of the Company's acquisitions, dispositions, and other significant transactions, including the impact of the Tax Act which allows for the unlimited carryover of net operating losses created in 2018 and beyond.

The increase in the valuation allowance during the nine months ended September 30, 2017 was comprised of multiple components. The increase included $85.0 million related to the removal of future timing differences as a result of the formation of the Blackstone Venture and termination of leases associated therewith. In addition, the Company increased its valuation allowance by $48.5 million upon the adoption of ASU 2016-09, Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting. The $48.5 million offset the increase to the Company's net operating loss carryforward position previously reflected in an additional paid-in capital pool, and accordingly, did not impact the current period income tax position. The remaining change of approximately $86.6 million for the nine months ended September 30, 2017 reflects the allowance established against that period's operating loss.

The Company recorded an aggregate deferred federal, state and local tax benefit of $15.4 million and $71.3 million as a result of the operating loss for the three and nine months ended September 30, 2018, respectively. The benefit for the three months ended September 30, 2018 includes a benefit from a decrease in the valuation allowance of $2.7 million. The benefit for the nine months ended September 30, 2018 was offset by an increase in the valuation allowance of $52.2 million. The change in the valuation allowance for the three and nine months ended September 30, 2018 is the result of the anticipated reversal of future tax liabilities offset by future tax deductions. The Company recorded an aggregate deferred federal, state, and local tax benefit of $91.3 million and $123.0 million as a result of the operating loss for the three and nine months ended September 30, 2017, respectively, which was offset by an increase in the valuation allowance of $59.6 million and $86.6 million, respectively.

The Company evaluates its deferred tax assets each quarter to determine if a valuation allowance is required based on whether it is more likely than not that some portion of the deferred tax asset would not be realized. The Company's valuation allowance as of September 30, 2018 and December 31, 2017 is $388.3 million and $336.1 million, respectively.

For the year ended December 31, 2017, the Company estimated the impact of the Tax Act on state income taxes reflected in its income tax benefit. Reasonable estimates for the Company's state and local provision continue to be made based on the Company's analysis of tax reform. These provisional amounts have not been adjusted for the three and nine months ended September 30, 2018 but may be adjusted in future periods during 2018 when additional information is obtained. In addition, the Tax Act limits the annual deductibility of a corporation's net interest expense unless it elects to be exempt from such deductibility limitation under the real property trade or business exception. The Company plans to elect the real property trade or business exception with the 2018 tax return. As such, the Company will be required to apply the alternative depreciation system ("ADS") to all current and future residential real property and qualified improvement property assets. This change did not have a material effect for the three and nine months ended September 30, 2018 but will impact future tax depreciation deductions and may impact the Company's valuation allowance. The Company is unable to estimate the future impact of this change at this time. Additional information that may affect the Company's provisional amounts would include further clarification and guidance on how the Internal Revenue Service will implement tax reform and further clarification and guidance on how state taxing authorities will implement tax reform and the related effect on the Company's state and local income tax returns, state and local net operating losses and corresponding valuation allowances.

The Company recorded interest charges related to its tax contingency reserve for cash tax positions for the three and nine months ended September 30, 2018 and September 30, 2017 which are included in income tax expense or benefit for the period. As of September 30, 2018, tax returns for years 2013 through 2017 are subject to future examination by tax authorities. In addition, the net operating losses from prior years are subject to adjustment under examination.