Commitments and Contingencies	3 Months Ended
Mar. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Commitments and Contingencies: Securities Class Action Litigation. On December 11, 2009, a putative securities class action was filed in the United States District Court for the Eastern District of Washington against Sterling and certain of our current and former officers. The court appointed a lead plaintiff on March 9, 2010. On June 18, 2010, the lead plaintiff filed a consolidated complaint (the “Complaint”). The Complaint purports to be brought on behalf of a class of persons who purchased or otherwise acquired Sterling's stock during the period from July 23, 2008 to October 15, 2009. The Complaint alleges that defendants violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 by failing to disclose the extent of Sterling's delinquent commercial real estate, construction and land development loans, properly record losses for impaired loans, and properly reserve for loan losses, thereby causing Sterling's stock price to be artificially inflated during the purported class period. Plaintiffs seek unspecified damages and attorneys' fees and costs. Sterling believes the lawsuit is without merit and intends to defend against it vigorously. On August 30, 2010, Sterling moved to dismiss the Complaint. On March 2, 2011, after complete briefing, the court held a hearing on the motion to dismiss. The court has not yet issued an order on the motion, but indicated that it intends to do so in the near future. Failure by Sterling to obtain a favorable resolution of the claims set forth in the complaint could have a material adverse effect on our business, results of operations and financial condition. Currently, a loss resulting from these claims is not considered probable or reasonably estimable in amount. ERISA Class Action Litigation. On January 20 and 22, 2010, two putative class action complaints were filed in the United States District Court for the Eastern District of Washington against Sterling, as well as certain of Sterling's current and former officers and directors. The two complaints were merged in a Consolidated Amended Complaint (the “Complaint”) filed on July 16, 2010 in the same court. The Complaint does not name all of the individuals named in the prior complaints, but it is expected that additional defendants will be added. The Complaint alleges that the defendants breached their fiduciary duties under sections 404 and 405 of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), with respect to the Sterling Savings Bank Employee Savings and Investment Plan (the “401(k) Plan”) and the FirstBank Northwest Employee Stock Ownership Plan (“ESOP”) (collectively, the "Plans”). Specifically, the Complaint alleges that the defendants breached their duties by investing assets of the Plans in Sterling's securities when it was imprudent to do so, and by investing such assets in Sterling securities when defendants knew or should have known that the price of those securities was inflated due to misrepresentations and omissions about Sterling's business practices. The business practices at issue include alleged over-reliance on risky construction loans; alleged inadequate loan reserves; alleged spiking increases in nonperforming assets, nonperforming loans, classified assets, and over 90-day delinquent loans; alleged inadequate accounting for rising loan payment shortfalls; alleged unsafe and unsound banking practices; and a capital base that was allegedly inadequate to withstand the significant deterioration in the real estate markets. The putative class periods are October 22, 2007 to the present for the 401(k) Plan class, and October 22, 2007 to November 14, 2008 for the ESOP class. The Complaint seeks damages of an unspecified amount and attorneys' fees and costs. On September 26, 2012, Sterling received a letter from the U.S. Department of Labor (the “Department of Labor”) containing similar allegations as those set forth in the Complaint, demanding that the violations alleged in the Department of Labor's letter be corrected and notifying Sterling that the Department of Labor may take legal action in connection with such allegations, including assessing a civil money penalty. Failure by Sterling to obtain a favorable resolution of the claims set forth in the Complaint or in the letter from the Department of Labor could have a material adverse effect on Sterling's business, results of operations, and financial condition. In January 2013, a tentative settlement was reached, pursuant to which Sterling agreed to pay $3.0 million to settle the claims. The settlement is subject to approval by the court and the Department of Labor. On March 29, 2013, the Court preliminarily approved the settlement, with the final fairness hearing set for July 11, 2013. Additionally, Sterling is involved in ongoing litigation, primarily related to its normal business operations. When establishing a liability for contingent litigation losses, Sterling determines a range of potential losses for each matter that is both probable and estimable, and records the amount it considers to be the best estimate within the range. For these matters and others where an unfavorable outcome is reasonably possible but not probable, there is no estimable range of possible losses. Sterling believes that the eventual outcome from these cases will not, individually or in the aggregate, have a material adverse effect on its consolidated financial position.

Commitments and Contingencies:

Securities Class Action Litigation. On December 11, 2009, a putative securities class action was filed in the United States District Court for the Eastern District of Washington against Sterling and certain of our current and former officers. The court appointed a lead plaintiff on March 9, 2010. On June 18, 2010, the lead plaintiff filed a consolidated complaint (the “Complaint”). The Complaint purports to be brought on behalf of a class of persons who purchased or otherwise acquired Sterling's stock during the period from July 23, 2008 to October 15, 2009. The Complaint alleges that defendants violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 by failing to disclose the extent of Sterling's delinquent commercial real estate, construction and land development loans, properly record losses for impaired loans, and properly reserve for loan losses, thereby causing Sterling's stock price to be artificially inflated during the purported class period. Plaintiffs seek unspecified damages and attorneys' fees and costs. Sterling believes the lawsuit is without merit and intends to defend against it vigorously. On August 30, 2010, Sterling moved to dismiss the Complaint. On March 2, 2011, after complete briefing, the court held a hearing on the motion to dismiss. The court has not yet issued an order on the motion, but indicated that it intends to do so in the near future. Failure by Sterling to obtain a favorable resolution of the claims set forth in the complaint could have a material adverse effect on our business, results of operations and financial condition. Currently, a loss resulting from these claims is not considered probable or reasonably estimable in amount.

ERISA Class Action Litigation. On January 20 and 22, 2010, two putative class action complaints were filed in the United States District Court for the Eastern District of Washington against Sterling, as well as certain of Sterling's current and former officers and directors. The two complaints were merged in a Consolidated Amended Complaint (the “Complaint”) filed on July 16, 2010 in the same court. The Complaint does not name all of the individuals named in the prior complaints, but it is expected that additional defendants will be added. The Complaint alleges that the defendants breached their fiduciary duties under sections 404 and 405 of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), with respect to the Sterling Savings Bank Employee Savings and Investment Plan (the “401(k) Plan”) and the FirstBank Northwest Employee Stock Ownership Plan (“ESOP”) (collectively, the "Plans”). Specifically, the Complaint alleges that the defendants breached their duties by investing assets of the Plans in Sterling's securities when it was imprudent to do so, and by investing such assets in Sterling securities when defendants knew or should have known that the price of those securities was inflated due to misrepresentations and omissions about Sterling's business practices. The business practices at issue include alleged over-reliance on risky construction loans; alleged inadequate loan reserves; alleged spiking increases in nonperforming assets, nonperforming loans, classified assets, and over 90-day delinquent loans; alleged inadequate accounting for rising loan payment shortfalls; alleged unsafe and unsound banking practices; and a capital base that was allegedly inadequate to withstand the significant deterioration in the real estate markets. The putative class periods are October 22, 2007 to the present for the 401(k) Plan class, and October 22, 2007 to November 14, 2008 for the ESOP class. The Complaint seeks damages of an unspecified amount and attorneys' fees and costs. On September 26, 2012, Sterling received a letter from the U.S. Department of Labor (the “Department of Labor”) containing similar allegations as those set forth in the Complaint, demanding that the violations alleged in the Department of Labor's letter be corrected and notifying Sterling that the Department of Labor may take legal action in connection with such allegations, including assessing a civil money penalty. Failure by Sterling to obtain a favorable resolution of the claims set forth in the Complaint or in the letter from the Department of Labor could have a material adverse effect on Sterling's business, results of operations, and financial condition. In January 2013, a tentative settlement was reached, pursuant to which Sterling agreed to pay $3.0 million to settle the claims. The settlement is subject to approval by the court and the Department of Labor. On March 29, 2013, the Court preliminarily approved the settlement, with the final fairness hearing set for July 11, 2013.

Additionally, Sterling is involved in ongoing litigation, primarily related to its normal business operations. When establishing a liability for contingent litigation losses, Sterling determines a range of potential losses for each matter that is both probable and estimable, and records the amount it considers to be the best estimate within the range. For these matters and others where an unfavorable outcome is reasonably possible but not probable, there is no estimable range of possible losses. Sterling believes that the eventual outcome from these cases will not, individually or in the aggregate, have a material adverse effect on its consolidated financial position.