Regulatory Capital Requirements (Tables)

12 Months Ended

Dec. 31, 2012

Regulatory Capital Requirements [Abstract]

Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations

As of December 31, 2012, the most recent notification from the Federal Deposit Insurance Corporation categorized Columbia Bank as well capitalized under the regulatory framework for prompt corrective action. To be categorized as well capitalized, an institution must maintain minimum total risk-based, Tier 1 risk-based, and Tier 1 leverage ratios as set forth in the following tables. There are no conditions or events since the notification that management believes have changed Columbia Bank’s category. The Company and its banking subsidiary’s actual capital amounts and ratios as of December 31, 2012 and 2011, are also presented in the following table.

	Actual				For Capital Adequacy Purposes				To Be Well Capitalized Under Prompt Corrective Action Provision
	Amount		Ratio		Amount		Ratio		Amount		Ratio
	(dollars in thousands)
As of December 31, 2012
Total Capital (to risk-weighted assets):
The Company	$	652,704	20.62	%	$	253,242	8.0	%	N/A		N/A
Columbia Bank	$	565,677	17.87	%	$	253,244	8.0	%	$	316,556	10.0	%
Tier 1 Capital (to risk-weighted assets):
The Company	$	612,584	19.35	%	$	126,621	4.0	%	N/A		N/A
Columbia Bank	$	525,556	16.60	%	$	126,622	4.0	%	$	189,933	6.0	%
Tier 1 Capital (to average assets):
The Company	$	612,584	12.78	%	$	191,778	4.0	%	N/A		N/A
Columbia Bank	$	525,556	11.07	%	$	189,986	4.0	%	$	237,483	5.0	%
As of December 31, 2011
Total Capital (to risk-weighted assets):
The Company	$	636,559	21.05	%	$	241,955	8.0	%	N/A		N/A
Columbia Bank	$	561,216	18.55	%	$	242,028	8.0	%	$	302,535	10.0	%
Tier 1 Capital (to risk-weighted assets):
The Company	$	598,485	19.79	%	$	120,978	4.0	%	N/A		N/A
Columbia Bank	$	523,131	17.29	%	$	121,014	4.0	%	$	181,521	6.0	%
Tier 1 Capital (to average assets):
The Company	$	598,485	12.96	%	$	184,780	4.0	%	N/A		N/A
Columbia Bank	$	523,131	11.45	%	$	182,747	4.0	%	$	228,434	5.0	%