Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Accounting Policies - Additional Information (Details)

v3.19.1
Basis of Presentation and Accounting Policies - Additional Information (Details) - USD ($)
3 Months Ended
Jan. 01, 2019
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Dec. 31, 2017
Basis Of Presentation And Accounting Policies [Line Items]          
Operating Lease, Right-of-Use Asset   $ 30,503,000      
Operating Lease, Liability   37,769,000      
Impact of adoption of new accounting standard   11,026,000      
Cumulative Effect on Retained Earnings, Tax   (5,160,000) $ (11,286,000)    
Contract with customer, liability   3,601,000 9,429,000 $ 1,327,000 $ 10,104,000
Capitalized interest costs, including allowance for funds used during construction, total   400,000      
Impairment of long-lived assets held-for-use   $ 0 2,900,000    
Equity method investment, other than temporary impairment     $ 1,200,000    
Effective income tax rate reconciliation, percent, total   13.40% 23.50%    
Class of warrant or right, exercise price of warrants or rights   $ 0.01      
Incremental common shares attributable to conversion of debt securities, total   2,183,708 4,070,500    
Restricted Stock          
Basis Of Presentation And Accounting Policies [Line Items]          
Antidilutive securities excluded from computation of earnings per share, amount   129,080 94,507    
Employee Stock Option          
Basis Of Presentation And Accounting Policies [Line Items]          
Antidilutive securities excluded from computation of earnings per share, amount   791,816 653,700    
Two Customers          
Basis Of Presentation And Accounting Policies [Line Items]          
Contract with customer, liability   $ 200,000      
Deferred Reimbursement And Deferred Reservation Fees          
Basis Of Presentation And Accounting Policies [Line Items]          
Contract with customer, liability   1,400,000      
Geographic Distribution, Foreign          
Basis Of Presentation And Accounting Policies [Line Items]          
Contract with customer, liability   $ 2,000,000      
Accounting Standards Update 2016-02 [Member]          
Basis Of Presentation And Accounting Policies [Line Items]          
Operating Lease, Right-of-Use Asset $ 33,700,000        
Operating Lease, Liability 31,900,000        
Accounting Standards Update 2016-02 [Member] | Change in Accounting Principle for Equipment, Office and Land Leases [Member]          
Basis Of Presentation And Accounting Policies [Line Items]          
Cumulative Effect on Retained Earnings, Net of Tax 1,700,000        
Accounting Standards Update 2016-02 [Member] | Change in Accounting Principle for Unamortized Deferred Gains [Member]          
Basis Of Presentation And Accounting Policies [Line Items]          
Cumulative Effect on Retained Earnings, Net of Tax 8,700,000        
Impact of adoption of new accounting standard 11,000,000        
Cumulative Effect on Retained Earnings, Tax $ 2,300,000