Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents	$ 120.9	$ 128.7	$ 102.1	$ 171.8
Restricted cash	24.3	20.2
Accounts receivable, net	465.3	487.1
Notes receivable, net	129.0	167.7
Inventories	270.1	248.5
Prepaid expenses, deposits and other current assets	126.0	123.3
Property and equipment, net	663.8	794.0
Investment in subsidiaries	0.0	0.0
Goodwill	2,991.0	3,013.7
Intangible assets, net	1,841.0	1,920.0
Intercompany balances	0.0	0.0
Software, net	431.1	485.9
Other assets	314.1	343.1
Total assets	7,376.6	7,732.2
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	49.6	50.3
Other current liabilities	668.9	603.6
Long-term debt, excluding current portion	8,033.8	8,156.7
Other long-term liabilities	374.3	417.1
Intercompany balances	0.0	0.0
Stockholders' (deficit) equity	(1,750.0)	(1,495.5)
Total liabilities and stockholders' (deficit) equity	7,376.6	7,732.2
Reportable Legal Entities | SGC (Parent and Issuer)
Assets
Cash and cash equivalents	42.7	43.2	17.3	37.9
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Notes receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses, deposits and other current assets	32.2	26.8
Property and equipment, net	8.1	8.2
Investment in subsidiaries	3,166.1	3,319.6
Goodwill	0.0	0.0
Intangible assets, net	196.5	138.3
Intercompany balances	0.0	0.0
Software, net	71.0	35.6
Other assets	270.1	232.5
Total assets	3,786.7	3,804.2
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	66.7	63.7
Long-term debt, excluding current portion	248.5	248.0
Other long-term liabilities	179.4	119.1
Intercompany balances	5,042.1	4,868.9
Stockholders' (deficit) equity	(1,750.0)	(1,495.5)
Total liabilities and stockholders' (deficit) equity	3,786.7	3,804.2
Reportable Legal Entities | SGI (Issuer)
Assets
Cash and cash equivalents	0.5	0.0	0.0	0.1
Restricted cash	0.0	0.0
Accounts receivable, net	58.2	94.6
Notes receivable, net	0.0	0.0
Inventories	37.9	36.9
Prepaid expenses, deposits and other current assets	17.5	7.0
Property and equipment, net	106.3	106.4
Investment in subsidiaries	859.5	838.1
Goodwill	188.3	186.0
Intangible assets, net	38.5	39.8
Intercompany balances	5,505.1	5,857.1
Software, net	22.9	32.7
Other assets	223.9	123.4
Total assets	7,058.6	7,322.0
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	43.0	43.0
Other current liabilities	194.0	150.5
Long-term debt, excluding current portion	7,774.2	7,890.3
Other long-term liabilities	12.1	14.5
Intercompany balances	0.0	0.0
Stockholders' (deficit) equity	(964.7)	(776.3)
Total liabilities and stockholders' (deficit) equity	7,058.6	7,322.0
Reportable Legal Entities | Guarantor Subsidiaries
Assets
Cash and cash equivalents	0.0	0.5	6.8	27.3
Restricted cash	24.2	20.0
Accounts receivable, net	193.2	223.0
Notes receivable, net	94.3	114.2
Inventories	93.2	104.2
Prepaid expenses, deposits and other current assets	35.2	51.0
Property and equipment, net	406.8	501.1
Investment in subsidiaries	888.1	819.0
Goodwill	1,931.7	1,934.0
Intangible assets, net	1,386.0	1,505.0
Intercompany balances	0.0	0.0
Software, net	285.5	358.0
Other assets	44.8	51.8
Total assets	5,383.0	5,681.8
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	206.9	238.8
Long-term debt, excluding current portion	0.0	0.0
Other long-term liabilities	517.4	502.1
Intercompany balances	552.3	966.8
Stockholders' (deficit) equity	4,106.4	3,974.1
Total liabilities and stockholders' (deficit) equity	5,383.0	5,681.8
Reportable Legal Entities | Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	84.8	85.0	78.0	106.5
Restricted cash	0.1	0.2
Accounts receivable, net	213.9	169.5
Notes receivable, net	34.7	53.5
Inventories	156.8	119.6
Prepaid expenses, deposits and other current assets	41.1	38.5
Property and equipment, net	166.1	189.8
Investment in subsidiaries	0.0	0.0
Goodwill	871.0	893.7
Intangible assets, net	220.0	236.9
Intercompany balances	89.3	0.0
Software, net	51.7	59.6
Other assets	217.9	241.7
Total assets	2,147.4	2,088.0
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	6.6	7.3
Other current liabilities	208.4	150.6
Long-term debt, excluding current portion	11.1	18.4
Other long-term liabilities	108.0	87.7
Intercompany balances	0.0	21.4
Stockholders' (deficit) equity	1,813.3	1,802.6
Total liabilities and stockholders' (deficit) equity	2,147.4	2,088.0
Eliminating Entries
Assets
Cash and cash equivalents	(7.1)	0.0	$ 0.0	$ 0.0
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Notes receivable, net	0.0	0.0
Inventories	(17.8)	(12.2)
Prepaid expenses, deposits and other current assets	0.0	0.0
Property and equipment, net	(23.5)	(11.5)
Investment in subsidiaries	(4,913.7)	(4,976.7)
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Intercompany balances	(5,594.4)	(5,857.1)
Software, net	0.0	0.0
Other assets	(442.6)	(306.3)
Total assets	(10,999.1)	(11,163.8)
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	(7.1)	0.0
Long-term debt, excluding current portion	0.0	0.0
Other long-term liabilities	(442.6)	(306.3)
Intercompany balances	(5,594.4)	(5,857.1)
Stockholders' (deficit) equity	(4,955.0)	(5,000.4)
Total liabilities and stockholders' (deficit) equity	$ (10,999.1)	$ (11,163.8)