Derivative Financial Instruments - Master Netting Arrangements (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	$ 135,940	$ 196,346
Net Amounts of Assets Presented in the Statement of Financial Position	135,920	196,276
Gross Assets Offset Under Master Netting Arrangements, Total	(20)	(70)
Gross Assets Subject To Master Netting Arrangement Not Offset	(123,447)	(181,547)
Cash Collateral Received Subject to Master Netting Arrangements	(4,810)	(5,080)
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	7,663	9,649
Gross Amounts of Recognized Liabilities	11,914	14,083
Gross Amounts offset in the Statement of Financial Position	(20)	(70)
Net Amounts of Liabilities Presented in the Statement of Financial Position	11,894	14,013
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(7,414)	(9,648)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	4,480	4,365
Derivative
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	18,904	23,357
Gross Amounts offset in the Statement of Financial Position	(20)	(70)
Net Amounts of Assets Presented in the Statement of Financial Position	18,884	23,287
Gross Assets Subject To Master Netting Arrangement Not Offset	(6,411)	(8,558)
Cash Collateral Received Subject to Master Netting Arrangements	(4,810)	(5,080)
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	7,663	9,649
Gross Amounts of Recognized Liabilities	11,914	14,083
Gross Amounts offset in the Statement of Financial Position	(20)	(70)
Net Amounts of Liabilities Presented in the Statement of Financial Position	11,894	14,013
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(7,414)	(9,648)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	4,480	4,365
Derivative | Interest rate swaps
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	6,025	6,492
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	6,025	6,492
Gross Assets Subject To Master Netting Arrangement Not Offset	(1,215)	(1,412)
Cash Collateral Received Subject to Master Netting Arrangements	(4,810)	(5,080)
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	11,175	15,096
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	11,175	15,096
Gross Assets Subject To Master Netting Arrangement Not Offset	(4,879)	(6,735)
Cash Collateral Received Subject to Master Netting Arrangements	0	0
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	6,296	8,361
Gross Amounts of Recognized Liabilities	10,043	12,183
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	10,043	12,183
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(5,880)	(8,282)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	4,163	3,901
Derivative | Client foreign currency options
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	233	504
Gross Amounts offset in the Statement of Financial Position	(20)	(70)
Net Amounts of Assets Presented in the Statement of Financial Position	213	434
Gross Assets Subject To Master Netting Arrangement Not Offset	(124)	(155)
Cash Collateral Received Subject to Master Netting Arrangements	0	0
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	89	279
Gross Amounts of Recognized Liabilities	233	504
Gross Amounts offset in the Statement of Financial Position	(20)	(70)
Net Amounts of Liabilities Presented in the Statement of Financial Position	213	434
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(89)	(279)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	124	155
Derivative | Client interest rate derivatives
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	1,471	1,265
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	1,471	1,265
Gross Assets Subject To Master Netting Arrangement Not Offset	(193)	(256)
Cash Collateral Received Subject to Master Netting Arrangements	0	0
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	1,278	1,009
Gross Amounts of Recognized Liabilities	1,638	1,396
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	1,638	1,396
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(1,445)	(1,087)
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	193	309
Reverse Repurchase Securities Borrowing And Similar Arrangements
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	117,036	172,989
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	117,036	172,989
Gross Assets Subject To Master Netting Arrangement Not Offset	(117,036)	(172,989)
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