Business Combinations (Details) (USD $)	12 Months Ended			10 Months Ended	12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Feb. 29, 2012	Dec. 31, 2012 First Independent Bank	Dec. 31, 2012 First Independent Bank	Feb. 29, 2012 First Independent Bank Branches Installments	Dec. 31, 2012 Minimum First Independent Bank	Dec. 31, 2012 Maximum First Independent Bank	Dec. 31, 2012 Evidence of credit deterioration	Feb. 29, 2012 Evidence of credit deterioration	Feb. 29, 2012 No Evidence of credit deterioration
Business Acquisition, Cost of Acquired Entity, Purchase Price [Abstract]
Net purchase price						$ 40,600,000
Cash paid						28,900,000
Contingent consideration fair value	15,442,000	0				11,700,000
First installment					12 months
Second installment					18 months
Number of installments payable						2
Potential cash payment range							0	17,000,000
Business Acquisition, Purchase Price Allocation, Noncurrent Assets [Abstract]
Additional branches acquired in Portland/Vancouver market						14
Cash and cash equivalents			150,045,000
Investments and MBS			187,465,000
Loans receivable, net			349,990,000
Goodwill	22,577,000	0	22,577,000
Core deposit intangible			11,974,000
Fixed assets			4,038,000
Other assets			10,886,000
Total assets acquired			736,975,000
Deposits			695,919,000
Other Liabilties			409,000
Total liabilities assumed			696,328,000
Net assets acquired			40,647,000
Business Acquisition, Pro Forma Information [Abstract]
Net interest income	311,159,000	326,916,000		20,145,000
Noninterest income	155,258,000	135,828,000		4,757,000
Net income	389,935,000	49,469,000		10,817,000
Earnigns per share - basic	$ 6.28	$ 0.80		$ 0.17
Earnings per share - diluted	$ 6.21	$ 0.79		$ 0.17
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period [Abstract]
Contractual cash flows										24,408,000
Expected prepayments and credit losses										7,220,000
Expected cash flows										17,188,000
Present value of expected cash flows										(15,265,000)
Accretable yield										1,923,000
Certain Loans Acquired in Transfer Not Accounted for as Held-to-maturity Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning Balance									0
Additions									1,923,000
Accretable yield									(756,000)
Reclassifications	165,000
Ending Balance									1,332,000
Loans Acquired, Not Accounted for as Debt Securities, Held-to-maturity Category [Abstract]
Unpaid principal of impaired loans	18,200,000
Carrying amount of purchase impaired loans	11,200,000
Unpaid principal balance and contractual interest											403,800,000
Cash flows not expected to be collected											12,700,000
Cash flow discounted on loans											21,800,000
Investment Income, Net, Amortization of Discount and Premium [Abstract]
2013	4,210,000
2014	2,796,000
2015	1,724,000
2016	1,031,000
2017	$ 679,000