Stockholders' Investment (Details) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended					12 Months Ended			12 Months Ended
	Jan. 04, 2013	Aug. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Aug. 14, 2013	Dec. 05, 2012	Dec. 31, 2013 Sargent Transportation Group	Dec. 31, 2012 Sargent Transportation Group	Dec. 31, 2007 Sargent Transportation Group	Dec. 31, 2013 Bullet [Member]	Dec. 31, 2012 Bullet [Member]	Dec. 11, 2009 Bullet [Member]
Stockholders' investment:
Common stock, voting rights				one
Issuance of common sock, shares		1,500,000	3,400,000
Price per share							$ 27.00	$ 17.25
Proceeds from issuance of common stock		$ 38,400,000	$ 55,300,000	$ 53,059,000	$ 57,119,000	$ 869,000
Underwriting discounts and commissions		2,300,000	3,400,000
Common Stock, Shares, Overallotment	525,000
Proceeds from Sale of Shares, Net of Underwriting Discount and Estimated Expenses	8,500,000
Additional expenses incurred for public offering		300,000
Number of securities called by warrants											2,269,263			1,746,971
Exercise price of warrants											13.39			8.37
Fair value of warrants on date of issue														$ 3,000,000
Warrants exercised									23,491	0		604,722	44,794