XML 48 R38.htm IDEA: XBRL DOCUMENT v3.19.2
Schedule of Outstanding Debt (Detail) - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Debt Instrument [Line Items]    
Secured long-term debt $ 297,795 $ 330,784
Less current portion (98,601) (101,713)
Total long-term debt 199,194 229,071
Secured Equipment Notes due in 2024 [Member]    
Debt Instrument [Line Items]    
Secured long-term debt 28,699 11,658
Secured Equipment Notes due in 2023 [Member]    
Debt Instrument [Line Items]    
Secured long-term debt 173,468 192,858
Secured Equipment Notes due in 2022 [Member]    
Debt Instrument [Line Items]    
Secured long-term debt 21,247 24,092
Secured Equipment Notes due in 2021 [Member]    
Debt Instrument [Line Items]    
Secured long-term debt 45,475 55,855
Secured Equipment Notes due in 2020 [Member]    
Debt Instrument [Line Items]    
Secured long-term debt 23,378 32,904
Secured Equipment Notes due in 2019 [Member]    
Debt Instrument [Line Items]    
Secured long-term debt $ 5,528 $ 13,417