Severance, Impairment and Other - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost And Reserve [Line Items]
Severance, impairment and other	$ 2,266	$ 2,417
Severance [Member]
Restructuring Cost And Reserve [Line Items]
Severance, impairment and other		1,189
Commercial Property [Member]
Restructuring Cost And Reserve [Line Items]
Severance, impairment and other	450
Software Systems [Member]
Restructuring Cost And Reserve [Line Items]
Severance, impairment and other	1,066	592
Land Parcel [Member]
Restructuring Cost And Reserve [Line Items]
Severance, impairment and other		400
Natural Disasters and Other Casualty Events [Member]
Restructuring Cost And Reserve [Line Items]
Severance, impairment and other	$ 750	$ 236