v3.3.1.900
Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Condensed Cash Flow Statements, Captions [Line Items]      
Net cash provided by operating activities $ 133,918 $ 119,519 $ 105,096
Investing activities:      
Purchase of property and equipment (57,123) (157,690) (102,726)
Proceeds from asset dispositions 5,236 10,266 42,197
Purchase of short-term investments (608,649) (465,094) (375,503)
Proceeds from sale of short-term investments 505,966 363,110 338,970
Refund of deposits on aircraft 6,010 11,506 8,161
Payments of deposits on aircraft (1,273) (6,948) (9,318)
Loan to unconsolidated affiliate   (200)  
Net cash used in investing activities (149,833) (245,050) (98,219)
Financing activities:      
Proceeds from issuance of Senior Notes due 2019   500,000  
Repayment of Senior Notes due 2018   (300,000)  
Premium and cost to retire debt early   (26,749)  
Debt issuance costs   (6,232)  
Proceeds from line of credit 232,660 264,253 164,771
Payments on line of credit (218,160) (300,253) (172,526)
Repurchase of common stock (2,448) (152) (1,037)
Net cash provided by (used in) financing activities 12,052 130,867 (8,792)
(Decrease) increase in cash (3,863) 5,336 (1,915)
Cash, beginning of year 6,270 934 2,849
Cash, end of year 2,407 6,270 934
Parent Company Only (issuer) [Member]      
Condensed Cash Flow Statements, Captions [Line Items]      
Net cash provided by operating activities 60,241 51,476 82,660
Investing activities:      
Purchase of property and equipment (57,123) (157,690) (102,726)
Proceeds from asset dispositions 5,236 10,266 42,197
Purchase of short-term investments (608,649) (465,094) (375,503)
Proceeds from sale of short-term investments 505,966 363,110 338,970
Refund of deposits on aircraft 6,010 11,506 8,161
Payments of deposits on aircraft (1,273) (6,948) (9,318)
Loan to unconsolidated affiliate   (200)  
Net cash used in investing activities (149,833) (245,050) (98,219)
Financing activities:      
Proceeds from issuance of Senior Notes due 2019   500,000  
Repayment of Senior Notes due 2018   (300,000)  
Premium and cost to retire debt early   (26,749)  
Debt issuance costs   (6,232)  
Proceeds from line of credit 232,660 264,253 164,771
Payments on line of credit (218,160) (300,253) (172,526)
Repurchase of common stock (2,448) (152) (1,037)
Due to/from affiliate, net 77,535 62,706 23,851
Net cash provided by (used in) financing activities 89,587 193,573 15,059
(Decrease) increase in cash (5) (1) (500)
Cash, beginning of year 51 52 552
Cash, end of year 46 51 52
Guarantor Subsidiaries [Member]      
Condensed Cash Flow Statements, Captions [Line Items]      
Net cash provided by operating activities [1] 73,677 68,043 22,436 [2]
Financing activities:      
Due to/from affiliate, net [1] (77,535) (62,706) (23,851) [2]
Net cash provided by (used in) financing activities [1] (77,535) (62,706) (23,851) [2]
(Decrease) increase in cash [1] (3,858) 5,337 (1,415) [2]
Cash, beginning of year [1] 6,219 882 [2] 2,297 [2]
Cash, end of year [1] $ 2,361 $ 6,219 $ 882 [2]
[1] Foreign subsidiaries represent minor subsidiaries and are included in the guarantor subsidiaries' amounts.
[2] Cash flows between the Parent Company and guarantor subsidiaries related to the Company's centralized cash management activities in 2013 have been adjusted to show the effects on net cash provided by operating and financing activities.