Business Combinations (Summary of Net Assets Purchased and Goodwill Recognized) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended
	May 01, 2014	Jul. 15, 2013	Jan. 09, 2013	Dec. 31, 2014	Dec. 31, 2013
Fair value adjustments:
(Goodwill) bargain purchase gain recognized				$ (119,029)	$ (29,365)
Washington Banking
Business Acquisition [Line Items]
Cost basis of net assets on merger date	181,782
Less: Consideration transferred	(269,619)
Other interest earning deposits	0
Investment securities	0
Loans held for sale	86
Fair value adjustments:
FDIC indemnification asset	357
Other real estate owned	387
Premises and equipment	(1,540)
Other intangible assets	10,216
Prepaid expenses and other assets	(6,416)
Deposits	(1,737)
Junior subordinated debentures	6,837
Accrued expenses and other liabilities	(3,590)
(Goodwill) bargain purchase gain recognized	(89,664)
Washington Banking | Noncovered Loans
Fair value adjustments:
Loans receivable	(12,811)
Washington Banking | Covered Loans
Fair value adjustments:
Loans receivable	6,384
Valley Bank
Business Acquisition [Line Items]
Cost basis of net assets on merger date		29,720
Less: Consideration transferred		(46,323)
Other interest earning deposits		162
Investment securities		0
Loans held for sale		0
Fair value adjustments:
FDIC indemnification asset		0
Other real estate owned		0
Premises and equipment		1,837
Other intangible assets		916
Prepaid expenses and other assets		198
Deposits		(9)
Junior subordinated debentures		0
Accrued expenses and other liabilities		149
(Goodwill) bargain purchase gain recognized		(16,353)
Valley Bank | Noncovered Loans
Fair value adjustments:
Loans receivable		(3,003)
Valley Bank | Covered Loans
Fair value adjustments:
Loans receivable		0
Northwest Commercial Bank
Business Acquisition [Line Items]
Cost basis of net assets on merger date			6,113
Less: Consideration transferred			(2,967)
Other interest earning deposits			7
Investment securities			(2)
Loans held for sale			0
Fair value adjustments:
FDIC indemnification asset			0
Other real estate owned			(1,301)
Premises and equipment			(69)
Other intangible assets			156
Prepaid expenses and other assets			2,394
Deposits			(11)
Junior subordinated debentures			0
Accrued expenses and other liabilities			(622)
(Goodwill) bargain purchase gain recognized			399
Northwest Commercial Bank | Noncovered Loans
Fair value adjustments:
Loans receivable			(3,299)
Northwest Commercial Bank | Covered Loans
Fair value adjustments:
Loans receivable			$ 0