Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Supplemental Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 196.4	$ 115.1
Restricted cash	27.0	24.7
Accounts receivable, net	492.7	495.0
Notes receivable, net	118.3	125.4
Inventories	255.2	242.3
Prepaid expenses, deposits and other current assets	135.8	114.1
Property and equipment, net	567.2	612.2
Investment in subsidiaries	0.0	0.0
Goodwill	2,961.3	2,888.4
Intangible assets, net	1,667.8	1,768.3
Intercompany balances	0.0	0.0
Software, net	356.7	409.1
Other assets	284.0	292.8
Total assets	7,062.4	7,087.4
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	39.9	49.3
Other current liabilities	630.7	643.1
Long-term debt, excluding current portion	8,048.9	8,024.9
Other long-term liabilities	319.4	305.8
Intercompany balances	0.0	0.0
Stockholders' (deficit) equity	(1,976.5)	(1,935.7)
Total liabilities and stockholders' (deficit) equity	7,062.4	7,087.4
Non-current restricted cash	16.3	17.1
Reportable Legal Entities | SGI (Issuer)
Assets
Cash and cash equivalents	3.9	1.7
Restricted cash	0.0	0.0
Accounts receivable, net	57.8	61.4
Notes receivable, net	0.0	0.0
Inventories	40.2	40.3
Prepaid expenses, deposits and other current assets	25.3	15.7
Property and equipment, net	84.9	98.4
Investment in subsidiaries	981.4	926.7
Goodwill	188.3	188.3
Intangible assets, net	35.1	37.5
Intercompany balances	5,405.8	5,415.1
Software, net	21.7	21.4
Other assets	336.1	236.5
Total assets	7,180.5	7,043.0
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	32.8	43.0
Other current liabilities	178.3	158.7
Long-term debt, excluding current portion	8,044.5	7,767.3
Other long-term liabilities	9.9	12.4
Intercompany balances	0.0	0.0
Stockholders' (deficit) equity	(1,085.0)	(938.4)
Total liabilities and stockholders' (deficit) equity	7,180.5	7,043.0
Reportable Legal Entities | SGC (Parent and Issuer)
Assets
Cash and cash equivalents	137.3	32.7
Restricted cash	0.0	0.0
Accounts receivable, net	0.1	0.0
Notes receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses, deposits and other current assets	9.7	11.6
Property and equipment, net	25.1	5.6
Investment in subsidiaries	3,200.0	3,000.7
Goodwill	0.0	0.0
Intangible assets, net	172.4	185.8
Intercompany balances	0.0	0.0
Software, net	70.7	74.7
Other assets	234.3	233.6
Total assets	3,849.6	3,544.7
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	101.6	100.5
Long-term debt, excluding current portion	0.0	248.7
Other long-term liabilities	167.8	159.0
Intercompany balances	5,556.7	4,972.2
Stockholders' (deficit) equity	(1,976.5)	(1,935.7)
Total liabilities and stockholders' (deficit) equity	3,849.6	3,544.7
Reportable Legal Entities | Guarantor Subsidiaries
Assets
Cash and cash equivalents	0.0	0.0
Restricted cash	26.9	24.6
Accounts receivable, net	202.8	199.2
Notes receivable, net	96.1	94.4
Inventories	93.1	83.1
Prepaid expenses, deposits and other current assets	44.5	45.6
Property and equipment, net	311.0	369.3
Investment in subsidiaries	954.7	944.0
Goodwill	1,932.4	1,931.6
Intangible assets, net	1,240.1	1,343.0
Intercompany balances	0.0	0.0
Software, net	216.3	264.6
Other assets	55.1	50.8
Total assets	5,173.0	5,350.2
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	198.6	216.3
Long-term debt, excluding current portion	0.0	0.0
Other long-term liabilities	549.4	468.8
Intercompany balances	189.1	559.5
Stockholders' (deficit) equity	4,235.9	4,105.6
Total liabilities and stockholders' (deficit) equity	5,173.0	5,350.2
Non-current restricted cash	15.6	16.4
Reportable Legal Entities | Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	60.6	81.8
Restricted cash	0.1	0.1
Accounts receivable, net	232.0	234.4
Notes receivable, net	22.2	31.0
Inventories	145.5	138.1
Prepaid expenses, deposits and other current assets	56.3	41.2
Property and equipment, net	170.0	154.9
Investment in subsidiaries	0.0	0.0
Goodwill	840.6	768.5
Intangible assets, net	220.2	202.0
Intercompany balances	340.0	116.6
Software, net	48.0	48.4
Other assets	159.8	173.5
Total assets	2,295.3	1,990.5
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	7.1	6.3
Other current liabilities	160.2	168.7
Long-term debt, excluding current portion	4.4	8.9
Other long-term liabilities	90.9	67.2
Intercompany balances	0.0	0.0
Stockholders' (deficit) equity	2,032.7	1,739.4
Total liabilities and stockholders' (deficit) equity	2,295.3	1,990.5
Non-current restricted cash	0.7	0.7
Eliminating Entries
Assets
Cash and cash equivalents	(5.4)	(1.1)
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Notes receivable, net	0.0	0.0
Inventories	(23.6)	(19.2)
Prepaid expenses, deposits and other current assets	0.0	0.0
Property and equipment, net	(23.8)	(16.0)
Investment in subsidiaries	(5,136.1)	(4,871.4)
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Intercompany balances	(5,745.8)	(5,531.7)
Software, net	0.0	0.0
Other assets	(501.3)	(401.6)
Total assets	(11,436.0)	(10,841.0)
Liabilities and stockholders' (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	(8.0)	(1.1)
Long-term debt, excluding current portion	0.0	0.0
Other long-term liabilities	(498.6)	(401.6)
Intercompany balances	(5,745.8)	(5,531.7)
Stockholders' (deficit) equity	(5,183.6)	(4,906.6)
Total liabilities and stockholders' (deficit) equity	$ (11,436.0)	$ (10,841.0)