Derivative Financial Instruments - Master Netting Arrangements (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	$ 194,796	$ 156,683
Net Amounts of Assets Presented in the Statement of Financial Position	194,753	156,461
Gross Assets Offset Under Master Netting Arrangements, Total	(43)	(222)
Gross Assets Subject To Master Netting Arrangement Not Offset	(174,321)	(144,195)
Cash Collateral Received Subject to Master Netting Arrangements	(5,580)	(6,110)
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	14,852	6,156
Gross Amounts of Recognized Liabilities	18,479	13,659
Gross Amounts offset in the Statement of Financial Position	(43)	(222)
Net Amounts of Liabilities Presented in the Statement of Financial Position	18,436	13,437
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(15,497)	(6,920)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	2,939	6,517
Derivative
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	26,770	23,326
Gross Amounts offset in the Statement of Financial Position	(43)	(222)
Net Amounts of Assets Presented in the Statement of Financial Position	26,727	23,104
Gross Assets Subject To Master Netting Arrangement Not Offset	(6,295)	(10,838)
Cash Collateral Received Subject to Master Netting Arrangements	(5,580)	(6,110)
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	14,852	6,156
Gross Amounts of Recognized Liabilities	18,479	13,659
Gross Amounts offset in the Statement of Financial Position	(43)	(222)
Net Amounts of Liabilities Presented in the Statement of Financial Position	18,436	13,437
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(15,497)	(6,920)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	2,939	6,517
Derivative | Interest rate swaps
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	7,027	9,005
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	7,027	9,005
Gross Assets Subject To Master Netting Arrangement Not Offset	(1,447)	(2,895)
Cash Collateral Received Subject to Master Netting Arrangements	(5,580)	(6,110)
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	0	0
Derivative | Foreign exchange forwards
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	18,281	12,352
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	18,281	12,352
Gross Assets Subject To Master Netting Arrangement Not Offset	(4,777)	(7,363)
Cash Collateral Received Subject to Master Netting Arrangements	0	0
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	13,504	4,989
Gross Amounts of Recognized Liabilities	16,827	11,658
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	16,827	11,658
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(13,964)	(5,720)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	2,863	5,938
Derivative | Client foreign currency options
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	225	1,411
Gross Amounts offset in the Statement of Financial Position	(43)	(222)
Net Amounts of Assets Presented in the Statement of Financial Position	182	1,189
Gross Assets Subject To Master Netting Arrangement Not Offset	(11)	(556)
Cash Collateral Received Subject to Master Netting Arrangements	0	0
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	171	633
Gross Amounts of Recognized Liabilities	225	1,411
Gross Amounts offset in the Statement of Financial Position	(43)	(222)
Net Amounts of Liabilities Presented in the Statement of Financial Position	182	1,189
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(171)	(633)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	11	556
Derivative | Client interest rate derivatives
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	1,237	558
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	1,237	558
Gross Assets Subject To Master Netting Arrangement Not Offset	(60)	(24)
Cash Collateral Received Subject to Master Netting Arrangements	0	0
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	1,177	534
Gross Amounts of Recognized Liabilities	1,427	590
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	1,427	590
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(1,362)	(567)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	65	23
Reverse Repurchase Securities Borrowing And Similar Arrangements
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	168,026	133,357
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	168,026	133,357
Gross Assets Subject To Master Netting Arrangement Not Offset	(168,026)	(133,357)
Cash Collateral Received Subject to Master Netting Arrangements	0	0
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	0	0
Gross Amounts of Recognized Liabilities	0	0
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	0	0
Gross Liabilities Subject To Master Netting Arrangement Not Offset	0	0
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	$ 0	$ 0