Stock Based Awards and Other Equity Instruments - Summary of RSU Activity For MSUs (Parenthetical) (Details) - MSUs - shares		12 Months Ended
	Nov. 01, 2019	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017	[1]	Nov. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share award issued		389,000		284,000		213,000
MSU's issued under incentive plan		121,000	[2],[3]	71,000	[4]
Employee Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of originally granted shares that may be earned upon performance achievement, maximum		125.00%
Percentage of originally granted shares that may be earned upon performance achievement, minimum		0.00%
Stock awards vesting term		MSU award provides for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2018 through December 31, 2020 relative to the TSR performance of the Nasdaq Composite Total Return Index.
Performance measurement period start date		Jan. 01, 2018
Performance measurement period end date		Dec. 31, 2020
Employee Stock | Dividend Equivalents
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
MSU's issued under incentive plan	42,477
Employee Stock | 2011 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of originally granted shares that may be earned upon performance achievement, maximum		200.00%
Percentage of originally granted shares that may be earned upon performance achievement, minimum		0.00%
Stock awards vesting term		MSUs provide for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2018 through December 31, 2020 relative to the TSR performance of the Nasdaq Composite Total Return Index.
Performance measurement period start date		Jan. 01, 2018
Performance measurement period end date		Dec. 31, 2020
Employee Stock | 2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of originally granted shares that may be earned upon performance achievement, maximum		200.00%
Percentage of originally granted shares that may be earned upon performance achievement, minimum		0.00%
Stock awards vesting term		MSUs which provide for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2019 through December 31, 2021 relative to the TSR performance of the Nasdaq Composite Total Return Index.
Performance measurement period start date		Jan. 01, 2019
Performance measurement period end date		Dec. 31, 2021
MSU's issued under incentive plan		78,050
CEO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share award issued								213,000

[1] Represents 213,000 market-based RSU or MSUs awarded to the Company’s CEO in November 2017. The MSU award provides for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2018 through December 31, 2020 relative to the TSR performance of the Nasdaq Composite Total Return Index. Based upon actual attainment relative to the target performance metric, the CEO has the ability to receive up to 125% of the target number of MSUs originally granted, or to be issued none at all.

[2] Inclusive of 42,477 dividend equivalents issued to employees holding non-vested MSU grant awards in conjunction with our special cash dividend declared on November 1, 2019, which will be payable to the holder subject to, and upon vesting of, the underlying awards.

[3] Inclusive of 78,050 MSUs which provide for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2019 through December 31, 2021 relative to the TSR performance of the Nasdaq Composite Total Return Index. Based upon actual attainment relative to the target performance metric, the grantee has the ability to receive up to 200% of the target number of MSUs originally granted, or to be issued none at all. These MSUs were granted under the 2018 Plan.

[4] MSUs provide for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2018 through December 31, 2020 relative to the TSR performance of the Nasdaq Composite Total Return Index. Based upon actual attainment relative to the target performance metric, the grantee has the ability to receive up to 200% of the target number of MSUs originally granted, or to be issued none at all. These MSUs were granted under the 2011 Plan.