Discontinued operations - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from discontinued operations	$ 88,883,000
SCO [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from transaction	98,800,000
Cash proceeds from discontinued operations	94,100,000
Cash divested	400,000
Direct selling costs	2,900,000
Income taxes attributable to the sale of component of the entity	1,400,000
U.S. LTL [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash divested	400,000
Direct selling costs	3,200,000
Cash proceeds from discontinued operations	2,000,000
Real estate debt and capital leases assumed by buyer	32,800,000
Cash deficits funded by buyer prior to sale closing	1,400,000
Capitalization of component of the entity	5,000,000
Net cash divested related to sale of U.S. LTL	5,200,000
Non-cash write-down of U.S. LTL net assets	49,700,000
Net loss in discontinued operations	$ (45,945,000)