Sale of Properties	12 Months Ended
Dec. 31, 2012
Sale of Properties [Abstract]
Sale of Distribution Centers	Sale of Properties In 2012, in conjunction with the construction of a new distribution center in McCook, Illinois and the relocation of the Company’s headquarters to Chicago, Illinois, the Company sold four properties; its Addison, Illinois distribution center, its Vernon Hills, Illinois distribution center, its former Des Plaines, Illinois headquarters and a Des Plaines, Illinois administrative building. The Company received cash proceeds of $12.3 million for the sale of the four properties, which were included in the MRO segment, resulting in a gain of $3.7 million. Operations currently conducted at the Addison, Illinois, distribution center will be transferred to the new McCook, Illinois facility during the first half of 2013. The Company has entered into arrangements to lease these facilities back from the buyer for transition purposes until the second quarter of 2013. In addition to these four property sales, the Company allowed the lease of another Des Plaines, Illinois facility to expire during the second quarter of 2012. In 2010, the Company sold its Dallas, Texas distribution center receiving cash proceeds of $2.0 million resulting in a gain of $1.7 million.

Sale of Properties

In 2012, in conjunction with the construction of a new distribution center in McCook, Illinois and the relocation of the Company’s headquarters to Chicago, Illinois, the Company sold four properties; its Addison, Illinois distribution center, its Vernon Hills, Illinois distribution center, its former Des Plaines, Illinois headquarters and a Des Plaines, Illinois administrative building. The Company received cash proceeds of $12.3 million for the sale of the four properties, which were included in the MRO segment, resulting in a gain of $3.7 million. Operations currently conducted at the Addison, Illinois, distribution center will be transferred to the new McCook, Illinois facility during the first half of 2013. The Company has entered into arrangements to lease these facilities back from the buyer for transition purposes until the second quarter of 2013.

In addition to these four property sales, the Company allowed the lease of another Des Plaines, Illinois facility to expire during the second quarter of 2012.

In 2010, the Company sold its Dallas, Texas distribution center receiving cash proceeds of $2.0 million resulting in a gain of $1.7 million.