Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements and Derivative Instruments Fair Value Measurements and Derivative Instruments (Derivative Financial Instruments) (Details)

v3.6.0.2
Fair Value Measurements and Derivative Instruments Fair Value Measurements and Derivative Instruments (Derivative Financial Instruments) (Details) - USD ($)
 12 Months Ended
Feb. 02, 2015
Dec. 31, 2016
Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Stock Appreciation Rights, Expiration Date 8 years    
Fair Value Assumptions, Volatility   37.50% 40.00%
Fair Value Assumptions, Risk Free Interest Rate   2.10% 2.10%
Unsecured Debt [Member] | Searchlight ALX, LP Promissory Note [Member]      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Face amount of debt $ 75,000,000.0    
Stock Appreciation Rights (SARs)      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Derivative stock appreciation rights, beginning balance   $ 32,820,000 $ 0
Issuance     21,660,000
Derivative stock appreciation rights, ending balance   29,700,000 32,820,000
Stock Appreciation Rights (SARs) | Other Income (Expense) [Member]      
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]      
Fair value adjustment at end of period, included in Other Income (Expense)   $ 3,120,000 $ 11,160,000
Class A Common Stock | Stock Appreciation Rights (SARs)      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Rights outstanding 3,000,000    
Exercise price of rights $ 13.00    
Class A Common Stock | Stock Appreciation Rights (SARs) | Searchlight ALX, LP Promissory Note [Member]      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Rights outstanding 3,000,000    
Exercise price of rights $ 13.00    
Minimum      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fair Value Assumptions, Expected Term   2 years 1 month 4 years
Maximum      
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fair Value Assumptions, Expected Term   6 years 1 month 8 years