Goodwill and Other Intangible Assets - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Goodwill
Goodwill acquired during the year (preliminary allocation)		$ 431,827
Title plant assets	$ 6,700	$ 6,700	$ 6,700
Sabadell United
Goodwill
Goodwill acquired during the year (preliminary allocation)	$ 431,800

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e961-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration