Regulatory Capital Requirements (Tables)

12 Months Ended

Dec. 31, 2015

Regulatory Capital Requirements [Abstract]

Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations

As of December 31, 2015, 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 CET1 risk-based, Tier 1 risk-based, total risk-based and Tier 1 leverage ratios as set forth in the following table. 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, 2015 and 2014 are 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, 2015
CET1 Capital (to risk-weighted assets):
The Company	$	852,731	11.94	%	$	321,370	4.5	%	N/A		N/A
Columbia Bank	$	839,127	11.76	%	$	321,168	4.5	%	$	463,909	6.5	%
Tier 1 Capital (to risk-weighted assets):
The Company	$	853,182	11.95	%	$	428,493	6.0	%	N/A		N/A
Columbia Bank	$	839,127	11.76	%	$	428,223	6.0	%	$	570,965	8.0	%
Total Capital (to risk-weighted assets):
The Company	$	924,284	12.94	%	$	571,324	8.0	%	N/A		N/A
Columbia Bank	$	910,229	12.75	%	$	570,965	8.0	%	$	713,706	10.0	%
Tier 1 Capital Leverage (to average assets):
The Company	$	853,182	10.03	%	$	340,420	4.0	%	N/A		N/A
Columbia Bank	$	839,127	9.89	%	$	339,405	4.0	%	$	424,256	5.0	%
As of December 31, 2014
Tier 1 Capital (to risk-weighted assets):
The Company	$	817,805	12.98	%	$	251,995	4.0	%	N/A		N/A
Columbia Bank	$	788,531	12.52	%	$	251,926	4.0	%	$	377,889	6.0	%
Total Capital (to risk-weighted assets):
The Company	$	890,029	14.13	%	$	503,989	8.0	%	N/A		N/A
Columbia Bank	$	860,755	13.67	%	$	503,852	8.0	%	$	629,816	10.0	%
Tier 1 Capital Leverage (to average assets):
The Company	$	817,805	10.57	%	$	309,579	4.0	%	N/A		N/A
Columbia Bank	$	788,531	9.79	%	$	322,029	4.0	%	$	402,537	5.0	%