Regulatory and legal developments - Additional Information (Detail) $ in Thousands	Jun. 25, 2015 USD ($) Plaintiff	Jun. 23, 2015 Plaintiff	May. 14, 2015 Plaintiff	Apr. 17, 2015 Plaintiff	Jun. 11, 2014 USD ($) Plaintiff	Aug. 05, 2013 Plaintiff claim
Hurst Financial Loans Litigation
Loss Contingencies [Line Items]
Litigation settlement | $					$ 10,530
Hurst Financial Loans Litigation | Settled Litigation
Loss Contingencies [Line Items]
Number of plaintiffs	2	5		2	500
Percent of total plaintiffs (more than)					90.00%
Litigation settlement | $	$ 4,500
Hurst Financial Loans Litigation | Pending Litigation
Loss Contingencies [Line Items]
Number of plaintiffs			7
Bellwether Trials
Loss Contingencies [Line Items]
Number of plaintiffs						8
Bellwether Jury Trial Claim Selected by Plaintiffs
Loss Contingencies [Line Items]
Bellwether jury trial claims pending | claim						4
Bellwether Jury Trial Claim Selected by Defendants
Loss Contingencies [Line Items]
Bellwether jury trial claims pending | claim						4
Hurst Financial Loans, Bellwether Trials, Including Stewart Title Company
Loss Contingencies [Line Items]
Number of plaintiffs						1