Business Segment Information - Information by Segment (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business segment information
Number of reportable segments | segment									2
Revenue:
Total revenue	$ 478.2	$ 396.1	$ 396.0	$ 353.5	$ 508.0	$ 419.8	$ 457.4	$ 423.7	$ 1,623.8	$ 1,808.9	$ 1,839.4
Operating Income:
Total operating income	70.7	28.2	31.6	$ 15.2	44.5	4.9	$ 35.4	$ 20.6	145.7	105.4	148.2
Impairment of assets	0.3	$ 2.5	$ 1.8		4.6	$ 6.9			4.6	11.5
Assets:
Total assets	1,730.9				1,864.8				1,730.9	1,864.8
Capital Expenditures
Total capital expenditures									34.2	33.8	50.3
Depreciation and Amortization
Total depreciation and amortization									53.3	59.7	61.3
Eliminations
Revenue:
Total revenue									(9.1)	(18.6)	(17.5)
Corporate, eliminations and other
Operating Income:
Total operating income									1.0	2.2	(0.2)
Assets:
Total assets	(63.5)				(64.1)				(63.5)	(64.1)
BSI
Operating Income:
Impairment of assets									4.6	6.4
Capital Expenditures
Total capital expenditures									30.1	31.5	44.9
Depreciation and Amortization
Total depreciation and amortization									50.5	55.1	56.4
BSI | Operating segments
Revenue:
Total revenue									1,499.2	1,674.6	1,709.5
Operating Income:
Total operating income									133.2	99.8	138.9
Assets:
Total assets	1,715.3				1,827.7				1,715.3	1,827.7
BEST
Operating Income:
Impairment of assets										5.1
Capital Expenditures
Total capital expenditures									4.1	2.3	5.4
Depreciation and Amortization
Total depreciation and amortization									2.8	4.6	4.9
BEST | Operating segments
Revenue:
Total revenue									133.7	152.9	147.4
Operating Income:
Total operating income									11.5	3.4	$ 9.5
Assets:
Total assets	$ 79.1				$ 101.2				$ 79.1	$ 101.2