Business Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 segment	Mar. 31, 2013	Dec. 31, 2013
Business Segment Information
Number of reporting segments	2
Revenue:
Total revenue	$ 423.7	$ 393.4
Operating Income:
Total operating income	20.6	12.2
Assets:
Total assets	2,027.7		1,988.3
Eliminations
Revenue:
Total revenue	(5.0)	(4.1)
Corporate, eliminations and other
Operating Income:
Total operating income	1.2	0.7
Assets:
Total assets	(79.3)		(83.5)
BSI | Operating segments
Revenue:
Total revenue	393.9	366.3
Operating Income:
Total operating income	16.6	10.6
Assets:
Total assets	1,964.8		1,925.3
BEST | Operating segments
Revenue:
Total revenue	34.8	31.2
Operating Income:
Total operating income	2.8	0.9
Assets:
Total assets	$ 142.2		$ 146.5