Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities (Common Securities, Preferred Securities, And Related Debentures) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Dec. 31, 2011
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Common Securities Issued	$ 3,043
Trust Preferred Securities Issued	241,750	[1]
Junior subordinated debentures	244,793		244,793
Bloomfield Hills Statutory Trust I [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Issuance Date	May 2004
Common Securities Issued	248
Trust Preferred Securities Issued	8,000	[1]
Coupon Rate	3.12%	[2]
Earliest Redemption Date (on or after	Jun. 17, 2009	[3]
Maturity	Jun. 2034
Junior subordinated debentures	8,248		8,248
Private Bancorp Statutory Trust II [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Issuance Date	Jun. 2005
Common Securities Issued	1,547
Trust Preferred Securities Issued	50,000	[1]
Coupon Rate	2.18%	[2]
Earliest Redemption Date (on or after	Sep. 15, 2010	[3]
Maturity	Sep. 2035
Junior subordinated debentures	51,547		51,547
Private Bancorp Statutory Trust III [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Issuance Date	Dec. 2005
Common Securities Issued	1,238
Trust Preferred Securities Issued	40,000	[1]
Coupon Rate	1.97%	[2]
Earliest Redemption Date (on or after	Dec. 15, 2010	[3]
Maturity	Dec. 2035
Junior subordinated debentures	41,238		41,238
Private Bancorp Statutory Trust IV [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Issuance Date	May 2008
Common Securities Issued	10
Trust Preferred Securities Issued	143,750	[1]
Coupon Rate	10.00%	[2]
Earliest Redemption Date (on or after	Jun. 13, 2013	[3]
Maturity	Jun. 2068
Junior subordinated debentures	143,760		143,760
Junior Subordinated Debt [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Common Securities Issued	3,043
Trust Preferred Securities Issued	$ 241,750	[1]
Three-Month LIBOR + 2.65% [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Increment Over Libor Of Long Term Debt	2.65%
Three-Month LIBOR + 1.71% [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Increment Over Libor Of Long Term Debt	1.71%
Three-Month LIBOR + 1.50% [Member]
Junior Subordinated Deferrable Interest Debentures Held By Trusts That Issued Guaranteed Capital Debt Securities [Line Items]
Increment Over Libor Of Long Term Debt	1.50%

[1] The trust preferred securities accrue distributions at a rate equal to the interest rate on and have a maturity identical to that of the related Debentures. The trust preferred securities will be redeemed upon maturity of the related Debentures.

[2] Reflects the coupon rate in effect at June 30, 2012. The coupon rate for the Bloomfield Hills Statutory Trust I is a variable rate and is based on six-month LIBOR plus 2.65%. The coupon rates for the PrivateBancorp Statutory Trusts II and III are at a variable rate based on six-month LIBOR plus 1.71% for Trust II and six-month LIBOR plus 1.50% for Trust III. The coupon rate for the PrivateBancorp Statutory Trust IV is fixed. Distributions for all of the Trusts are payable quarterly. We have the right to defer payment of interest on the Debentures at any time or from time to time for a period not exceeding ten years in the case of the Debentures held by Trust IV, and five years in the case of all other Debentures, without causing an event of default under the related indenture, provided no extension period may extend beyond the stated maturity of the Debentures. During such extension period, distributions on the trust preferred securities would also be deferred, and our ability to pay dividends on our common stock would be restricted. The Federal Reserve has the ability to prevent interest payments on the Debentures.

[3] The trust preferred securities are subject to mandatory redemption, in whole or in part, upon repayment of the Debentures at maturity or their earlier redemption. Subject to restrictions relating to our participation in the TARP CPP, the Debentures are redeemable in whole or in part prior to maturity at any time after the dates shown in the table, and in the case of Trust IV earlier at our discretion if certain events occur. It is anticipated that adoption of currently proposed capital rules would constitute a capital treatment event that would allow us to redeem early if certain conditions are satisfied, including those set forth in the replacement capital covenant to the extent then applicable. In addition, in any event, we may redeem only after we have obtained Federal Reserve approval, if then required under applicable guidelines or regulations.