Junior Subordinated Debentures (Junior Subordinated Debentures) (Details) (USD $) In Thousands, unless otherwise specified						6 Months Ended																																		6 Months Ended
	Jun. 30, 2014		Dec. 31, 2013	Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust II [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust III [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust IV [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust V [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Master Trust I [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Master Trust IB [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Sterling Capital Trust III [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Sterling Capital Trust IV [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Sterling Capital Statutory Trust V [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Sterling Capital Trust VI [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Sterling Capital Trust VII [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Sterling Capital Trust VIII [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Sterling Capital Trust IX [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Lynnwood Financial Statutory Trust I [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Lynnwood Financial Statutory Trust II [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Fair Value [Member] Klamath First Capital Trust I [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] HB Capital Trust I [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Humboldt Bancorp Statutory Trust I [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Humboldt Bancorp Statutory Trust II [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Humboldt Bancorp Statutory Trust III [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] CIB Capital Trust [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Western Sierra Statutory Trust I [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Western Sierra Statutory Trust II [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Western Sierra Statutory Trust III [Member]		Jun. 30, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Western Sierra Statutory Trust IV [Member]
Junior Subordinated Debentures [Line Items]
Issue Date						October 2002		October 2002		December 2003		December 2003		August 2007		September 2007		April 2003		May 2003		May 2003		June 2003		June 2006		September 2006		July 2007		March 2003		June 2005		July 2001				March 2000		February 2001		December 2001		September 2003		November 2002		July 2001		December 2001		September 2003		September 2003
Issued Amount	$ 475,427			$ 379,390		$ 20,619		$ 30,928		$ 10,310		$ 10,310		$ 41,238		$ 20,619		$ 14,433		$ 10,310		$ 20,619		$ 10,310		$ 56,702		$ 51,547		$ 46,392		$ 9,279		$ 10,310		$ 15,464		$ 96,037		$ 5,310		$ 5,155		$ 10,310		$ 27,836		$ 10,310		$ 6,186		$ 10,310		$ 10,310		$ 10,310
AT FAIR VALUE	246,077		87,274	246,077	[1]	14,946	[1]	22,619	[1]	7,061	[1]	7,039	[1]	23,082	[1]	13,607	[1]	11,026	[1]	7,788	[1]	15,642	[1]	7,766	[1]	32,894	[1]	30,270	[1]	26,110	[1]	6,956	[1]	6,309	[1]	12,962	[1]
AT AMORTIZED COST	101,737		101,899																																			101,737	[1]	6,189	[1]	5,800	[1]	11,244	[1]	30,278	[1]	11,110	[1]	6,186	[1]	10,310	[1]	10,310	[1]	10,310	[1]
Carrying Value	$ 347,814	[1]
Debt Instrument, Interest Rate, Stated Percentage																																								10.875%		10.20%
Rate						LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]							LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]	LIBOR	[2]
Basis spread on LIBOR						3.35%	[2]	3.45%	[2]	2.85%	[2]	2.85%	[2]	1.35%	[2]	2.75%	[2]	3.25%	[2]	3.15%	[2]	3.25%	[2]	3.20%	[2]	1.53%	[2]	1.63%	[2]	1.40%	[2]	3.15%	[2]	1.80%	[2]	3.75%	[2]							3.60%	[2]	2.95%	[2]	3.45%	[2]	3.58%	[2]	3.60%	[2]	2.90%	[2]	2.90%	[2]
Effective Rate						4.93%	[3]	5.02%	[3]	4.49%	[3]	4.51%	[3]	2.82%	[3]	4.52%	[3]	4.55%	[3]	4.47%	[3]	4.59%	[3]	4.55%	[3]	3.03%	[3]	3.17%	[3]	2.90%	[3]	4.51%	[3]	3.32%	[3]	4.88%	[3]			8.43%	[3]	8.39%	[3]	3.03%	[3]	2.50%	[3]	3.01%	[3]	3.80%	[3]	3.83%	[3]	3.13%	[3]	3.13%	[3]
Maturity Date						October 2032		November 2032		January 2034		March 2034		September 2037		December 2037		April 2033		May 2033		June 2033		September 2033		June 2036		December 2036		October 2037		March 2033		June 2035		July 2031				March 2030		February 2031		December 2031		September 2033		November 2032		July 2031		December 2031		September 2033		September 2033

[1] Includes purchase accounting adjustments, net of accumulated amortization, for junior subordinated debentures assumed in connection with previous mergers as well as fair value adjustments related to trusts recorded at fair value.

[2] Contractual interest rate of junior subordinated debentures.

[3] Effective interest rate based upon the carrying value as of June 30, 2014.