Junior Subordinated Debentures (Junior Subordinated Debentures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 475,427
AT AMORTIZED COST	101,254	$ 101,576
Carrying Value	356,711
Junior Subordinated Debt, at Fair Value [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	379,390
AT FAIR VALUE	255,457
Junior Subordinated Debt, at Fair Value [Member] | Umpqua Statutory Trust II [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	20,619
AT FAIR VALUE	$ 15,427
Rate	LIBOR
Basis spread on LIBOR	3.35%
Effective Rate	4.91%
Junior Subordinated Debt, at Fair Value [Member] | Umpqua Statutory Trust III [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 30,928
AT FAIR VALUE	$ 23,320
Rate	LIBOR
Basis spread on LIBOR	3.45%
Effective Rate	5.06%
Junior Subordinated Debt, at Fair Value [Member] | Umpqua Statutory Trust IV [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT FAIR VALUE	$ 7,319
Rate	LIBOR
Basis spread on LIBOR	2.85%
Effective Rate	4.47%
Junior Subordinated Debt, at Fair Value [Member] | Umpqua Statutory Trust V [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT FAIR VALUE	$ 7,292
Rate	LIBOR
Basis spread on LIBOR	2.85%
Effective Rate	4.77%
Junior Subordinated Debt, at Fair Value [Member] | Umpqua Master Trust I [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 41,238
AT FAIR VALUE	$ 24,268
Rate	LIBOR
Basis spread on LIBOR	1.35%
Effective Rate	3.16%
Junior Subordinated Debt, at Fair Value [Member] | Umpqua Master Trust IB [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 20,619
AT FAIR VALUE	$ 14,063
Rate	LIBOR
Basis spread on LIBOR	2.75%
Effective Rate	4.78%
Junior Subordinated Debt, at Fair Value [Member] | Sterling Capital Trust III [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 14,433
AT FAIR VALUE	$ 11,311
Rate	LIBOR
Basis spread on LIBOR	3.25%
Effective Rate	4.57%
Junior Subordinated Debt, at Fair Value [Member] | Sterling Capital Trust IV [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT FAIR VALUE	$ 7,994
Rate	LIBOR
Basis spread on LIBOR	3.15%
Effective Rate	4.53%
Junior Subordinated Debt, at Fair Value [Member] | Sterling Capital Statutory Trust V [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 20,619
AT FAIR VALUE	$ 16,040
Rate	LIBOR
Basis spread on LIBOR	3.25%
Effective Rate	4.95%
Junior Subordinated Debt, at Fair Value [Member] | Sterling Capital Trust VI [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT FAIR VALUE	$ 7,969
Rate	LIBOR
Basis spread on LIBOR	3.20%
Effective Rate	4.45%
Junior Subordinated Debt, at Fair Value [Member] | Sterling Capital Trust VII [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 56,702
AT FAIR VALUE	$ 34,540
Rate	LIBOR
Basis spread on LIBOR	1.53%
Effective Rate	3.34%
Junior Subordinated Debt, at Fair Value [Member] | Sterling Capital Trust VIII [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 51,547
AT FAIR VALUE	$ 31,708
Rate	LIBOR
Basis spread on LIBOR	1.63%
Effective Rate	3.48%
Junior Subordinated Debt, at Fair Value [Member] | Sterling Capital Trust IX [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 46,392
AT FAIR VALUE	$ 27,241
Rate	LIBOR
Basis spread on LIBOR	1.40%
Effective Rate	2.94%
Junior Subordinated Debt, at Fair Value [Member] | Lynnwood Financial Statutory Trust I [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 9,279
AT FAIR VALUE	$ 7,144
Rate	LIBOR
Basis spread on LIBOR	3.15%
Effective Rate	4.87%
Junior Subordinated Debt, at Fair Value [Member] | Lynnwood Financial Statutory Trust II [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT FAIR VALUE	$ 6,599
Rate	LIBOR
Basis spread on LIBOR	1.80%
Effective Rate	3.61%
Junior Subordinated Debt, at Fair Value [Member] | Klamath First Capital Trust I [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 15,464
AT FAIR VALUE	$ 13,222
Rate	LIBOR
Basis spread on LIBOR	3.75%
Effective Rate	4.95%
Junior Subordinated Debt, at Amortized Cost [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 96,037
AT AMORTIZED COST	101,254
Junior Subordinated Debt, at Amortized Cost [Member] | HB Capital Trust I [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	5,310
AT AMORTIZED COST	$ 6,106
Debt Instrument, Interest Rate, Stated Percentage	10.875%
Effective Rate	8.54%
Junior Subordinated Debt, at Amortized Cost [Member] | Humboldt Bancorp Statutory Trust I [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 5,155
AT AMORTIZED COST	$ 5,741
Debt Instrument, Interest Rate, Stated Percentage	10.20%
Effective Rate	8.48%
Junior Subordinated Debt, at Amortized Cost [Member] | Humboldt Bancorp Statutory Trust II [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT AMORTIZED COST	$ 11,164
Rate	LIBOR
Basis spread on LIBOR	3.60%
Effective Rate	3.33%
Junior Subordinated Debt, at Amortized Cost [Member] | Humboldt Bancorp Statutory Trust III [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 27,836
AT AMORTIZED COST	$ 30,083
Rate	LIBOR
Basis spread on LIBOR	2.95%
Effective Rate	2.78%
Junior Subordinated Debt, at Amortized Cost [Member] | Cib Capital Trust [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT AMORTIZED COST	$ 11,044
Rate	LIBOR
Basis spread on LIBOR	3.45%
Effective Rate	3.16%
Junior Subordinated Debt, at Amortized Cost [Member] | Western Sierra Statutory Trust I [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 6,186
AT AMORTIZED COST	$ 6,186
Rate	LIBOR
Basis spread on LIBOR	3.58%
Effective Rate	3.91%
Junior Subordinated Debt, at Amortized Cost [Member] | Western Sierra Statutory Trust II [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT AMORTIZED COST	$ 10,310
Rate	LIBOR
Basis spread on LIBOR	3.60%
Effective Rate	4.13%
Junior Subordinated Debt, at Amortized Cost [Member] | Western Sierra Statutory Trust III [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT AMORTIZED COST	$ 10,310
Rate	LIBOR
Basis spread on LIBOR	2.90%
Effective Rate	3.22%
Junior Subordinated Debt, at Amortized Cost [Member] | Western Sierra Statutory Trust IV [Member]
Junior Subordinated Debentures [Line Items]
Issued Amount	$ 10,310
AT AMORTIZED COST	$ 10,310
Rate	LIBOR
Basis spread on LIBOR	2.90%
Effective Rate	3.22%