Guarantor Condensed Consolidating Financial Statements (Condensed Consolidating Statement Of Cash Flows) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Net cash provided by (used in) operating activities	$ 165,850	$ 122,213
Cash flows from investing activities:
Increase (decrease)in restricted cash	14,556	(11,726)
Change in fixed maturity securities-restricted	(14,612)
Funding of GTI note receivable	(7,500)
Proceeds from sale of property and equipment	57,240	16,357
Capital expenditures	(131,102)	(111,158)
Payments received on notes receivable	3,202	3,784
Expenditures on assets held for sale	(2,223)	(4,987)
Payments received on assets held for sale	10,340	6,232
Payments received on equipment sale receivables	5,496
Other investing activities	(500)
Net cash used in investing activities	(65,103)	(101,498)
Cash flows from financing activities:
Proceeds from issuance of class A common stock, net of issuance costs		62,994
Payment of deferred loan costs	(9,009)	(3,425)
Borrowings under accounts receivable securitization	174,000	86,000
Repayment of accounts receivable securitization	(151,000)	(81,500)
Repayment of long-term debt and capital leases	(171,433)	(87,872)
Proceeds from long-term debt	10,000
Other financing activities	126	250
Net cash used in financing activities	(147,316)	(23,553)
Net increase (decrease) in cash and cash equivalents	(46,569)	(2,838)
Cash and cash equivalents at beginning of period	82,084	47,494
Cash and cash equivalents at end of period	35,515	44,656
Swift Transportation Company [Member]
Net cash provided by (used in) operating activities	25,110
Cash flows from financing activities:
Proceeds from issuance of class A common stock, net of issuance costs		62,994
Other financing activities	126	250
Net funding (to) from affiliates	(9,122)	(59,455)
Net cash used in financing activities	(8,996)	3,789
Net increase (decrease) in cash and cash equivalents	16,114	3,789
Cash and cash equivalents at beginning of period	11,132	1,561
Cash and cash equivalents at end of period	27,246	5,350
Swift Services Holdings, Inc. (Issuer) [Member]
Net cash provided by (used in) operating activities	6,520
Cash flows from financing activities:
Payment of deferred loan costs		(910)
Net funding (to) from affiliates	(6,520)	910
Net cash used in financing activities	(6,520)
Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	151,107	163,890
Cash flows from investing activities:
Funding of GTI note receivable	(7,500)
Proceeds from sale of property and equipment	57,238	16,253
Capital expenditures	(130,012)	(108,228)
Payments received on notes receivable	3,202	3,784
Expenditures on assets held for sale	(2,223)	(4,987)
Payments received on assets held for sale	10,340	6,232
Payments received on equipment sale receivables	5,496
Dividend from subsidiary	6,700
Funding of intercompany notes	(787)	(3,899)
Payments received on intercompany notes	604	2,047
Other investing activities	(500)
Net cash used in investing activities	(57,442)	(88,798)
Cash flows from financing activities:
Payment of deferred loan costs	(9,009)	(1,631)
Repayment of long-term debt and capital leases	(171,167)	(87,672)
Proceeds from long-term debt	10,000
Net funding (to) from affiliates	10,120	9,485
Net cash used in financing activities	(160,056)	(79,818)
Net increase (decrease) in cash and cash equivalents	(66,391)	(4,726)
Cash and cash equivalents at beginning of period	64,717	35,844
Cash and cash equivalents at end of period	(1,674)	31,118
Non-Guarantor Subsidiaries [Member]
Net cash provided by (used in) operating activities	(16,887)	(41,677)
Cash flows from investing activities:
Increase (decrease)in restricted cash	14,556	(11,726)
Change in fixed maturity securities-restricted	(14,612)
Proceeds from sale of property and equipment	2	104
Capital expenditures	(1,090)	(2,930)
Net cash used in investing activities	(1,144)	(14,552)
Cash flows from financing activities:
Payment of deferred loan costs		(884)
Borrowings under accounts receivable securitization	174,000	86,000
Repayment of accounts receivable securitization	(151,000)	(81,500)
Repayment of long-term debt and capital leases	(266)	(200)
Dividend to parent	(6,700)
Proceeds from intercompany notes	787	3,899
Repayment of intercompany notes	(604)	(2,047)
Net funding (to) from affiliates	5,522	49,060
Net cash used in financing activities	21,739	54,328
Net increase (decrease) in cash and cash equivalents	3,708	(1,901)
Cash and cash equivalents at beginning of period	6,235	10,089
Cash and cash equivalents at end of period	9,943	8,188
Eliminations For Consolidation [Member]
Cash flows from investing activities:
Dividend from subsidiary	(6,700)
Funding of intercompany notes	787	3,899
Payments received on intercompany notes	(604)	(2,047)
Net cash used in investing activities	(6,517)	1,852
Cash flows from financing activities:
Dividend to parent	6,700
Proceeds from intercompany notes	(787)	(3,899)
Repayment of intercompany notes	604	2,047
Net cash used in financing activities	$ 6,517	$ (1,852)