Junior Subordinated Debentures (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 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	$ 245,299	$ 245,294
Junior Subordinated Debt
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate, weighted average	2.38%
Amount	245,299
Junior Subordinated Debt | Sterling Capital Trust IX
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	1.65%
Amount	46,392
Junior Subordinated Debt | Sterling Capital Trust VIII
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	1.87%
Amount	51,547
Junior Subordinated Debt | Sterling Capital Trust VII
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	1.77%
Amount	56,702
Junior Subordinated Debt | Lynnwood Capital Trust II
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	2.04%
Amount	10,310
Junior Subordinated Debt | Sterling Capital Trust VI
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.44%
Amount	10,310
Junior Subordinated Debt | Sterling Capital Statutory Trust V
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.50%
Amount	20,619
Junior Subordinated Debt | Sterling Capital Trust IV
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.39%
Amount	10,310
Junior Subordinated Debt | Sterling Capital Trust III
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.49%
Amount	14,433
Junior Subordinated Debt | Lynnwood Capital Trust I
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	3.40%
Amount	9,429
Junior Subordinated Debt | Klamath First Capital Trust I
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Rate	4.15%
Amount	$ 15,247