Junior Subordinated Debentures (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Average Term of Junior Subordinated Debentures	30 years
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Amount	$ 245,298	$ 245,294
Junior Subordinated Debt [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Weighted Average Rate	2.39%
Amount	245,298
Junior Subordinated Debt [Member] | Sterling Capital Trust IX [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	1.67%
Amount	46,392
Junior Subordinated Debt [Member] | Sterling Capital Trust VIII [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	1.88%
Amount	51,547
Junior Subordinated Debt [Member] | Sterling Capital Trust VII [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	1.78%
Amount	56,702
Junior Subordinated Debt [Member] | Lynnwood Capital Trust II [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	2.05%
Amount	10,310
Junior Subordinated Debt [Member] | Sterling Capital Trust VI [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.45%
Amount	10,310
Junior Subordinated Debt [Member] | Sterling Capital Statutory Trust V [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.50%
Amount	20,619
Junior Subordinated Debt [Member] | Sterling Capital Trust IV [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.41%
Amount	10,310
Junior Subordinated Debt [Member] | Sterling Capital Trust III [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.52%
Amount	14,433
Junior Subordinated Debt [Member] | Lynnwood Capital Trust I [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.40%
Amount	9,430
Junior Subordinated Debt [Member] | Klamath First Capital Trust I [Member]
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	4.15%
Amount	$ 15,245