Regulatory Matters (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Parent Company [Member]
Regulatory Capital [Abstract]
Total Capital Actual Amount	$ 2,184,884		$ 2,167,954
Total Capital for Capital Adequacy Purposes Amount	1,335,532		1,291,923
Total Capital Actual Ratio	13.09%	[1]	13.42%	[1]
Total Capital for Adequacy Purposes Ratio	8.00%	[1]	8.00%	[1]
Tier 1 Capital Actual Amount	1,975,182		1,938,806
Tier 1 Capital for Adequacy Purposes Amount	667,766		645,962
Tier 1 Capital Actual Ratio	11.83%	[1]	12.01%	[1]
Tier 1 Capital for Adequacy Purposes Ratio	4.00%	[1]	4.00%	[1]
Tier 1 Leverage Capital Actual Amount	1,975,182		1,938,806
Tier 1 Leverage Capital for Adequacy Purposes Amount	907,937		863,674
Tier 1 Leverage Capital Actual Ratio	8.70%	[1]	8.98%	[1]
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	[1]	4.00%	[1]
Subsidiaries [Member]
Regulatory Capital [Abstract]
Total Capital Actual Amount	2,425,188		2,448,280
Total Capital for Capital Adequacy Purposes Amount	1,319,765		1,277,222
Total Capital to be Well Capitalized Amount	1,649,707	[2]	1,596,527	[2]
Total Capital Actual Ratio	14.70%	[1]	15.34%	[1]
Total Capital for Adequacy Purposes Ratio	8.00%	[1]	8.00%	[1]
Total Capital to be Well Capitalized Ratio	10.00%	[1]	10.00%	[1]
Tier 1 Capital Actual Amount	2,217,987		2,247,307
Tier 1 Capital for Adequacy Purposes Amount	659,883		638,611
Tier 1 Capital To Be Well Capitalized Amount	989,824	[2]	957,916	[2]
Tier 1 Capital Actual Ratio	13.44%	[1]	14.08%	[1]
Tier 1 Capital for Adequacy Purposes Ratio	4.00%	[1]	4.00%	[1]
Tier 1 Capital To Be Well Capitalized Ratio	6.00%	[1]	6.00%	[1]
Tier 1 Leverage Capital Actual Amount	2,217,987		2,247,307
Tier 1 Leverage Capital for Adequacy Purposes Amount	896,419		853,553
Tier 1 Leverage Capital To Be Well Capitalized Amount	$ 1,120,524	[2]	$ 1,066,941	[2]
Tier 1 Leverage Capital Actual Ratio	9.90%	[1]	10.53%	[1]
Tier 1 Leverage Capital for Adequacy Purposes Ratio	4.00%	[1]	4.00%	[1]
Tier 1 Leverage Capital To Be Well Capitalized Ratio	5.00%	[1]	5.00%	[1]

[1]  Total Capital ratio is defined as Tier 1 capital plus Tier 2 capital divided by total risk-weighted assets. The Tier 1 Capital ratio is defined as Tier 1 capital divided by total risk-weighted assets. The leverage ratio is defined as Tier 1 capital divided by the most recent quarter’s average total assets.

[2]  Prompt corrective action provisions are not applicable at the bank holding company level.