Accumulated Other Comprehensive Income (Loss) - Reclassifications out of Accumulated Other Comprehensive Loss (Detail) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Amortization of defined pension and other postretirement benefit items:
Amortization of net actuarial gains, before income taxes	$ 0.3
Deferred income tax expense on pension liability adjustments	(0.1)
Gains reclassified into loss, net of income taxes	$ 0.2

Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e689-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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