Share Based Compensation - Additional Information (Details) - USD ($)			1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 08, 2018	Apr. 12, 2017	Jul. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental expense recognized from modification				$ 600,000		$ 600,000
Total cost of share based payment plans				$ 1,424,000	$ 7,918,000	11,547,000	$ 34,182,000
General And Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total cost of share based payment plans						11,500,000
Management Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total cost of share based payment plans							$ 32,900,000
Management Incentive Plan | General And Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total cost of share based payment plans						$ 10,900,000
Performance Shares | Stock Incentive Plan 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percent of equity reserved for directors, officers and other employees		7.50%
Performance Shares | Management Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting description						During 2017, Management Incentive Plan Grants (the “Initial MIP Grants”) were made to members of the board of directors (the “Board”), officers, and other employees of the Company subject to the conditions and performance requirements provided in the grants, including the limitations that one-third of the Initial MIP Grants will vest, if at all, at such time when the total enterprise value of the Company equals or exceeds $6.0 billion based upon the volume weighted average price of the common stock during a consecutive 30-day period, that one-third of the Initial MIP Grants will vest, if at all, at such time when the total enterprise value of the Company equals or exceeds 110% of $6.0 billion based upon the volume weighted average price of the common stock during a consecutive 30-day period, and, that if any Initial MIP Grants do not vest before the fifth anniversary of the Effective Date, as defined in Note 10, such Initial MIP Grants shall automatically expire.
Performance Shares | Management Incentive Plan | Vest One-third Upon Reaching a Total Enterprise Value Equals or Exceeds $6.0 Billion
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage		0.33%
Total enterprise value		$ 6,000,000,000
Performance Shares | Management Incentive Plan | Vest One-third Upon Reaching a Total Enterprise Value Equals or Exceeds 110% of $6.0 Billion or $6.6 Billion
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage		0.33%
Total enterprise value		$ 6,000,000,000
Percentage of enterprise value		110.00%
Performance Shares | Amendment and Restatement of Stock Incentive Plan 2017 | Outside Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incentive awards available for grant value, maximum limit during a single calendar year	$ 750,000
Time-based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Plan modification unvested portion exchange units percentage			100.00%
Time-based Restricted Stock Units | May 25, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units vesting date			May 25, 2019
Time-based Restricted Stock Units | May 25, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units vesting date			May 25, 2020
Time-based Restricted Stock Units | May 25, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units vesting date			May 25, 2021