Junior Subordinated Debentures (Junior Subordinated Debentures) (Details) (USD $) In Thousands, unless otherwise specified							9 Months Ended																		9 Months Ended
	Sep. 30, 2013		Dec. 31, 2012	Sep. 30, 2013 Estimated Fair Value [Member]		Dec. 31, 2012 Estimated Fair Value [Member]	Sep. 30, 2013 Estimated Fair Value [Member] Umpqua Statutory Trust II [Member]		Sep. 30, 2013 Estimated Fair Value [Member] Umpqua Statutory Trust III [Member]		Sep. 30, 2013 Estimated Fair Value [Member] Umpqua Statutory Trust IV [Member]		Sep. 30, 2013 Estimated Fair Value [Member] Umpqua Statutory Trust V [Member]		Sep. 30, 2013 Estimated Fair Value [Member] Umpqua Master Trust I [Member]		Sep. 30, 2013 Estimated Fair Value [Member] Umpqua Master Trust IB [Member]		Sep. 30, 2013 Amortized Cost [Member]		Sep. 30, 2013 Amortized Cost [Member] HB Capital Trust I [Member]		Sep. 30, 2013 Amortized Cost [Member] Humboldt Bancorp Statutory Trust I [Member]		Sep. 30, 2013 Amortized Cost [Member] Humboldt Bancorp Statutory Trust II [Member]		Sep. 30, 2013 Amortized Cost [Member] Humboldt Bancorp Statutory Trust III [Member]		Sep. 30, 2013 Amortized Cost [Member] CIB Capital Trust [Member]		Sep. 30, 2013 Amortized Cost [Member] Western Sierra Statutory Trust I [Member]		Sep. 30, 2013 Amortized Cost [Member] Western Sierra Statutory Trust II [Member]		Sep. 30, 2013 Amortized Cost [Member] Western Sierra Statutory Trust III [Member]		Sep. 30, 2013 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	86,718		85,081	86,718	[1]	85,081	14,713	[1]	22,276	[1]	6,935	[1]	6,915	[1]	22,496	[1]	13,383	[1]
AT AMORTIZED COST	101,979		110,985	71,553		78,529													101,979	[1]	6,231	[1]	5,829	[1]	11,284	[1]	30,377	[1]	11,142	[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	$ 188,697	[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							5.07%	[3]	5.16%	[3]	4.64%	[3]	4.63%	[3]	2.94%	[3]	4.63%	[3]			8.37%	[3]	8.35%	[3]	3.04%	[3]	2.51%	[3]	3.04%	[3]	3.85%	[3]	3.85%	[3]	3.17%	[3]	3.17%	[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							3.35%	[2]	3.45%	[2]	2.85%	[2]	2.85%	[2]	1.35%	[2]	2.75%	[2]							3.60%	[2]	2.95%	[2]	3.45%	[2]	3.58%	[2]	3.60%	[2]	2.90%	[2]	2.90%	[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 September 30, 2013.