Junior Subordinated Debentures (Junior Subordinated Debentures) (Details) (USD $) In Thousands, unless otherwise specified						3 Months Ended																		3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013	Mar. 31, 2014 Junior Subordinated Debt, at Fair Value [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust II [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust III [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust IV [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Statutory Trust V [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Master Trust I [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Fair Value [Member] Umpqua Master Trust IB [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] HB Capital Trust I [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Humboldt Bancorp Statutory Trust I [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Humboldt Bancorp Statutory Trust II [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Humboldt Bancorp Statutory Trust III [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] CIB Capital Trust [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Western Sierra Statutory Trust I [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Western Sierra Statutory Trust II [Member]		Mar. 31, 2014 Junior Subordinated Debt, at Amortized Cost [Member] Western Sierra Statutory Trust III [Member]		Mar. 31, 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				March 2000		February 2001		December 2001		September 2003		November 2002		July 2001		December 2001		September 2003		September 2003
Issued Amount	$ 230,061			$ 134,024		$ 20,619		$ 30,928		$ 10,310		$ 10,310		$ 41,238		$ 20,619		$ 96,037		$ 5,310		$ 5,155		$ 10,310		$ 27,836		$ 10,310		$ 6,186		$ 10,310		$ 10,310		$ 10,310
AT FAIR VALUE	87,800		87,274	87,800	[1]	14,865	[1]	22,499	[1]	7,019	[1]	6,998	[1]	22,887	[1]	13,532	[1]
AT AMORTIZED COST	101,818		101,899															101,818	[1]	6,203	[1]	5,809	[1]	11,257	[1]	30,313	[1]	11,120	[1]	6,186	[1]	10,310	[1]	10,310	[1]	10,310	[1]
Debt Instrument, Interest Rate, Stated Percentage																				10.875%	[2]	10.20%	[2]
Carrying Value	$ 189,618	[1]
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]
Effective Rate						4.97%	[3]	5.07%	[3]	4.54%	[3]	4.54%	[3]	2.85%	[3]	4.55%	[3]			8.41%	[3]	8.38%	[3]	3.03%	[3]	2.49%	[3]	3.02%	[3]	3.82%	[3]	3.83%	[3]	3.14%	[3]	3.14%	[3]
Maturity Date						October 2032		November 2032		January 2034		March 2034		September 2037		December 2037				March 2030		February 2031		December 2031		September 2033		November 2032		July 2031		December 2031		September 2033		September 2033
Redemption Date						October 2007		November 2007		January 2009		March 2009		September 2012		December 2012				March 2010		February 2011		December 2006		September 2008		November 2007		July 2006		December 2006		September 2008		September 2008
Basis spread on LIBOR						4.97%	[2]	5.07%	[2]	4.54%	[2]	4.54%	[2]	2.85%	[2]	4.55%	[2]							3.03%	[2]	2.49%	[2]	3.02%	[2]	3.82%	[2]	3.83%	[2]	3.14%	[2]	3.14%	[2]

[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 March 31, 2014.