Earnings Per Share, Accumulated Other Comprehensive Loss, Dividend Restrictions and Other Regulatory Matters (Detail) - Schedule of capital amounts and ratios (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Tier 1 capital to total average assets, Ratio	9.00%
Actual [Member] | First Financial [Member]
Tier 1 capital to total average assets, Amount (in Dollars)	$ 341,952	[1]	$ 337,908	[1]
Tier 1 capital to total average assets, Ratio	10.72%	[1]	10.54%	[1]
Tier I capital to risk-based assets, Amount (in Dollars)	341,952	[1]	337,908	[1]
Tier I capital to risk-based assets, Ratio	15.30%	[1]	14.89%	[1]
Risk-based capital to risk-based assets, Amount (in Dollars)	370,636	[1]	366,897	[1]
Risk-based capital to risk-based assets, Ratio	16.58%	[1]	16.16%	[1]
Actual [Member] | First Federal [Member]
Tier 1 capital to total average assets, Amount (in Dollars)	326,547		319,555
Tier 1 capital to total average assets, Ratio	10.24%		9.97%
Tier I capital to risk-based assets, Amount (in Dollars)	326,547		319,555
Tier I capital to risk-based assets, Ratio	14.63%		14.10%
Risk-based capital to risk-based assets, Amount (in Dollars)	355,185		348,503
Risk-based capital to risk-based assets, Ratio	15.92%		15.37%
For Capital Adequacy Purposes [Member] | First Financial [Member]
Tier 1 capital to total average assets, Amount (in Dollars)	127,646	[1]	128,287	[1]
Tier 1 capital to total average assets, Ratio	4.00%	[1]	4.00%	[1]
Tier I capital to risk-based assets, Amount (in Dollars)	89,409	[1]	90,804	[1]
Tier I capital to risk-based assets, Ratio	4.00%	[1]	4.00%	[1]
Risk-based capital to risk-based assets, Amount (in Dollars)	178,819	[1]	181,608	[1]
Risk-based capital to risk-based assets, Ratio	8.00%	[1]	8.00%	[1]
For Capital Adequacy Purposes [Member] | First Federal [Member]
Tier 1 capital to total average assets, Amount (in Dollars)	127,579		128,201
Tier 1 capital to total average assets, Ratio	4.00%		4.00%
Tier I capital to risk-based assets, Amount (in Dollars)	89,258		90,685
Tier I capital to risk-based assets, Ratio	4.00%		4.00%
Risk-based capital to risk-based assets, Amount (in Dollars)	178,516		181,370
Risk-based capital to risk-based assets, Ratio	8.00%		8.00%
To Be Well-Capitalized Under Prompt Corrective Action Provisions [Member] | First Federal [Member]
Tier 1 capital to total average assets, Amount (in Dollars)	159,474	[1]	160,252	[1]
Tier 1 capital to total average assets, Ratio	5.00%	[1]	5.00%	[1]
Tier I capital to risk-based assets, Amount (in Dollars)	133,887	[1]	136,028	[1]
Tier I capital to risk-based assets, Ratio	6.00%	[1]	6.00%	[1]
Risk-based capital to risk-based assets, Amount (in Dollars)	$ 223,146	[1]	$ 226,713	[1]
Risk-based capital to risk-based assets, Ratio	10.00%	[1]	10.00%	[1]

[1] Bank holding companies are not subject to the prompt corrective action provision of the Federal Deposit Insurance Act.