Business Combinations (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended		0 Months Ended	3 Months Ended	9 Months Ended		0 Months Ended		3 Months Ended	9 Months Ended	0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Apr. 18, 2014 Sterling Financial Corporation [Member]	Sep. 30, 2014 Sterling Financial Corporation [Member]	Sep. 30, 2014 Sterling Financial Corporation [Member]	Jun. 20, 2014 Sterling Financial Corporation [Member] branches	Oct. 02, 2013 Financial Pacific Holding Corp [Member]	Jul. 02, 2013 Financial Pacific Holding Corp [Member]	Sep. 30, 2014 Financial Pacific Holding Corp [Member]	Sep. 30, 2014 Financial Pacific Holding Corp [Member]	Oct. 02, 2013 Financial Pacific Holding Corp [Member] Minimum [Member]	Oct. 02, 2013 Financial Pacific Holding Corp [Member] Maximum [Member]	Apr. 18, 2014 Equity Option [Member] Sterling Financial Corporation [Member]	Apr. 18, 2014 Restricted Stock Units (RSUs) [Member] Sterling Financial Corporation [Member]
Business Acquisition [Line Items]
Loans							$ 7,000,000,000
Equity issuable, share conversion ratio							1.671										1.7896	1.7896
Cash conversion, per share							$ 2.18
Tax deductible goodwill								0	0				0	0
Securities sold under agreements to repurchase expected to be repaid							500,000,000
Aggregate consideration to acquire entity							2,132,467,000				158,000,000
Cash paid							136,200,000					156,110,000
Fair value of common shares issued							1,939,497,000				1,900,000
Number of branches expected to be divested to Banner Bank										6
Disposal Group, Including Discontinued Operation, Deposits										211,500,000
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net										88,300,000
Vesting period of equity consideration															2 years	3 years
Merger related expenses	8,632,000	4,856,000	72,146,000	7,197,000				8,632,000	72,146,000				0
Goodwill	1,785,407,000		1,785,407,000		764,305,000	668,172,000	1,021,102,000					96,777,000
Revenues													17,200,000	49,500,000
Non-interest expense	182,558,000	95,604,000	493,207,000	269,297,000									4,200,000	12,100,000
Net income (loss)	58,989,000	23,477,000	94,974,000	73,091,000	98,361,000								4,600,000	12,800,000
Business Combination, Acquiree, Loans, Fair Value							6,700,000,000
Business Combination, Acquiree, Discount on Loans							$ 230,500,000