Guarantor Information - Guarantor Condensed Consolidating Statement of Cash Flows Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by (used in) operating activities - continuing operations	$ (21.0)	$ (19.2)
Cash provided by (used in) operating activities - discontinued operations	4.0	0.4
Net cash provided by (used in) operating activities	(17.0)	(18.8)
Cash flows from investing activities:
Capital expenditures	(57.3)	(35.1)
Proceeds from the sale of business assets	11.1
Cash used in investing activities - continuing operations	(46.2)	(35.1)
Cash provided by investing activities - discontinued operations	26.8	(1.7)
Net cash provided by (used in) investing activities	(19.4)	(36.8)
Cash flows from financing activities:
Issuance of long-term debt		248.8
Long-term debt payments	(0.8)	(195.2)
Deferred acquisition payments	(15.0)	(10.0)
Fees paid related to financing activities		(3.0)
Dividends paid	(11.3)	(11.2)
Share-based compensation plan activities	1.1	(0.4)
Net cash provided by (used in) financing activities	(26.0)	29.0
Effect of exchange rate changes on cash and cash equivalents	5.8	(5.5)
Net change in cash and cash equivalents	(56.6)	(32.1)
Cash and cash equivalents at beginning of period	258.0	166.8	$ 166.8
Cash and cash equivalents at end of period	201.4	134.7	258.0
Reportable Legal Entities [Member] | Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by (used in) operating activities - continuing operations	25.6	22.1
Net cash provided by (used in) operating activities	25.6	22.1
Cash flows from investing activities:
Capital expenditures	(0.2)	(0.2)
Cash used in investing activities - continuing operations	(0.2)	(0.2)
Net cash provided by (used in) investing activities	(0.2)	(0.2)
Cash flows from financing activities:
Deferred acquisition payments	(15.0)	(10.0)
Fees paid related to financing activities		(0.3)
Dividends paid	(11.3)	(11.2)
Share-based compensation plan activities	1.1	(0.4)
Net cash provided by (used in) financing activities	(25.2)	(21.9)
Net change in cash and cash equivalents	0.2
Cash and cash equivalents at beginning of period	0.3
Cash and cash equivalents at end of period	0.5		0.3
Reportable Legal Entities [Member] | Eagle Spinco Inc [Member]
Cash flows from financing activities:
Long-term debt payments		(194.4)
Intercompany financing		194.4
Reportable Legal Entities [Member] | Guarantor Subsidiaries Excluding Eagle Spinco Inc [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by (used in) operating activities - continuing operations	(35.7)	(24.9)
Cash provided by (used in) operating activities - discontinued operations	8.1	5.0
Net cash provided by (used in) operating activities	(27.6)	(19.9)
Cash flows from investing activities:
Capital expenditures	(55.7)	(32.2)
Proceeds from the sale of business assets	0.1
Cash used in investing activities - continuing operations	(55.6)	(32.2)
Cash provided by investing activities - discontinued operations	7.3	(0.7)
Net cash provided by (used in) investing activities	(48.3)	(32.9)
Cash flows from financing activities:
Issuance of long-term debt		248.8
Long-term debt payments	(0.8)	(0.8)
Intercompany financing		(194.4)
Fees paid related to financing activities		(2.7)
Distribution to affiliate	(4.4)
Net cash provided by (used in) financing activities	(5.2)	50.9
Net change in cash and cash equivalents	(81.1)	(1.9)
Cash and cash equivalents at beginning of period	161.7	78.2	78.2
Cash and cash equivalents at end of period	80.6	76.3	161.7
Reportable Legal Entities [Member] | Guarantor Subsidiaries Including Eagle Spinco Inc [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by (used in) operating activities - continuing operations	(35.7)	(24.9)
Cash provided by (used in) operating activities - discontinued operations	8.1	5.0
Net cash provided by (used in) operating activities	(27.6)	(19.9)
Cash flows from investing activities:
Capital expenditures	(55.7)	(32.2)
Proceeds from the sale of business assets	0.1
Cash used in investing activities - continuing operations	(55.6)	(32.2)
Cash provided by investing activities - discontinued operations	7.3	(0.7)
Net cash provided by (used in) investing activities	(48.3)	(32.9)
Cash flows from financing activities:
Issuance of long-term debt		248.8
Long-term debt payments	(0.8)	(195.2)
Fees paid related to financing activities		(2.7)
Distribution to affiliate	(4.4)
Net cash provided by (used in) financing activities	(5.2)	50.9
Net change in cash and cash equivalents	(81.1)	(1.9)
Cash and cash equivalents at beginning of period	161.7	78.2	78.2
Cash and cash equivalents at end of period	80.6	76.3	161.7
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by (used in) operating activities - continuing operations	(2.1)	(16.4)
Cash provided by (used in) operating activities - discontinued operations	(4.1)	(4.6)
Net cash provided by (used in) operating activities	(6.2)	(21.0)
Cash flows from investing activities:
Capital expenditures	(1.4)	(2.7)
Proceeds from the sale of business assets	11.0
Cash used in investing activities - continuing operations	9.6	(2.7)
Cash provided by investing activities - discontinued operations	19.5	(1.0)
Net cash provided by (used in) investing activities	29.1	(3.7)
Cash flows from financing activities:
Distribution to affiliate	(4.4)
Net cash provided by (used in) financing activities	(4.4)
Effect of exchange rate changes on cash and cash equivalents	5.8	(5.5)
Net change in cash and cash equivalents	24.3	(30.2)
Cash and cash equivalents at beginning of period	96.0	88.6	88.6
Cash and cash equivalents at end of period	120.3	$ 58.4	$ 96.0
Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by (used in) operating activities - continuing operations	(8.8)
Net cash provided by (used in) operating activities	(8.8)
Cash flows from financing activities:
Distribution to affiliate	8.8
Net cash provided by (used in) financing activities	$ 8.8