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Equity Based Compensation Plans (Details) |  | 1 Months Ended | 12 Months Ended | 24 Months Ended
--- | --- | --- | --- | ---
Dec. 09, 2014 shares | Dec. 31, 2013 shares | Dec. 31, 2018 USD ($) $ / shares shares | Dec. 31, 2017 USD ($) $ / shares shares | Dec. 31, 2016 USD ($) $ / shares shares | Dec. 09, 2015 | Dec. 31, 2011 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares authorized | shares |  |  | 2,000,000 |  |  |  |
Accelerated share-based compensation cost |  |  | $ 3,500,000 |  |  |  |
Intrinsic value of the options outstanding and fully vested |  |  | $ 12,500,000 | $ 11,300,000 |  |  |
Average fair value of stock options granted (in dollars per share) | $ / shares |  |  | $ 26.13 | $ 22.41 | $ 21.65 |  |
Cap on the appreciation of the market price over the exercise price, option 1 |  |  | $ 100 | $ 100 | $ 100 |  |
Cap on the appreciation of the market price over the exercise price, option 2 |  |  | 125 | 125 | 125 |  |
Stock Options [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Share based compensation expense |  |  | 12,100,000 | 9,800,000 | 8,500,000 |  |
Stock-based compensation capitalized |  |  | 2,000,000 | 1,500,000 | 500,000 |  |
Intrinsic value of options exercised |  |  | 3,100,000 | $ 16,700,000 | $ 11,900,000 |  |
Unrecognized compensation cost |  |  | $ 6,000,000 |  |  |  |
Unrecognized compensation cost, period for recognition |  |  | 2 years 1 month 15 days |  |  |  |
Restricted Stock [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Unrecognized compensation cost |  |  | $ 11,400,000 |  |  |  |
Unrecognized compensation cost, period for recognition |  |  | 2 years 8 months 1 day |  |  |  |
Granted (in shares) | shares |  |  | 51,945 | 62,706 | 49,183 |  |
2015 LTIP Units [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Unrecognized compensation cost, period for recognition |  |  | 6 years 6 months |  |  |  |
Granted (in shares) | shares | 44,750 |  |  |  |  |  |
Units issued subject only to performance measurement | shares | 24,000 |  |  |  |  |  |
Vesting percentage of units per year | 20.00% |  |  |  |  |  |
Option grants to officers and employees vesting period | 5 years |  |  |  |  |  |
Percent of awards earned |  |  |  |  |  | 95.75% |
Conversion ratio, incentive units |  |  | 1 |  |  |  |
Liquidity measurement period |  |  | 10 years |  |  |  |
Measurement period |  |  | 10 years |  |  |  |
Series Z Incentive Units [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Granted (in shares) | shares |  | 50,500 |  |  |  |  | 154,500
Option grants to officers and employees vesting period |  | 4 years |  |  |  |  |
Conversion ratio, incentive units |  |  |  |  |  |  | 1
Incentive units conversion ratio |  |  |  |  |  |  | one-for-one
Series Z Incentive Units [Member] | Minimum [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting percentage of units per year |  |  |  |  |  |  | 0.00%
Option grants to officers and employees vesting period |  |  | 8 years |  |  |  |
Series Z Incentive Units [Member] | Maximum [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting percentage of units per year |  |  |  |  |  |  | 14.00%
Option grants to officers and employees vesting period |  |  | 15 years |  |  |  |
Long Term Incentive Plan 2014 Units [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Unrecognized compensation cost, period for recognition |  |  | 1 year |  |  |  |
Vesting percentage of units per year |  | 25.00% |  |  |  |  |
Conversion ratio, incentive units |  |  | 1 |  |  |  |
Liquidity measurement period |  |  | 10 years |  |  |  |
Measurement period |  |  | 10 years |  |  |  |
Vesting percentage for 2011 Z 1 Units to be convertible |  |  |  |  |  |  | 100.00%
Long Term Incentive Plans - Z Units and 2014 LTIP Units [Member] |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Share based compensation expense |  |  | $ 800,000 | $ 1,500,000 | $ 2,400,000 |  |
Stock-based compensation capitalized |  |  | 200,000 | $ 500,000 | $ 600,000 |  |
Unrecognized compensation cost |  |  | $ 900,000 |  |  |  |
Granted (in shares) | shares |  |  | 0 | 0 | 0 |  |
Intrinsic value of vested and unvested LTIP units |  |  | $ 58,000,000 |  |  |  |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(ii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Unrecognized cost of unvested share-based compensation awards. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Additional share-based compensation cost recognized as a result of an occurrence of an event that accelerates its recognition. + References No definition available. + Details
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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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