Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2014
Tax Credit carry forward period	20 years
Federal NMTC Investment [Member]
Period of tax credit earning	7 years
Low Income Housing Investments [Member]
Period of tax credit earning	10 years
Minimum [Member] | State NMTC Investment [Member]
Period of tax credit earning	3 years
Maximum [Member] | State NMTC Investment [Member]
Period of tax credit earning	5 years