Fair Value (Details) - Fair Value Measurements - USD ($) $ in Thousands		Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Trading securities:
Total trading securities		$ 17,038		$ 17,460
Securities available-for-sale:
CDOs		31,870	$ 32,004	33,774	$ 18,369	$ 18,436	$ 18,309
Total available-for-sale securities		1,151,418		1,187,009
Level 1
Trading securities:
Money market funds		2,366		1,725
Mutual funds		14,672		15,735
Total trading securities		17,038		17,460
Securities available-for-sale:
U.S. treasury securities		0		0
U.S. agency securities		0		0
CMOs		0		0
MBSs		0		0
Municipal securities		0		0
CDOs		0		0
Corporate debt securities		0		0
Equity securities		0		0
Total available-for-sale securities		0		0
Mortgage servicing rights	[1]	0		0
Derivative assets	[1]	0		0
Liabilities:
Derivative liabilities	[2]	0		0
Level 2
Trading securities:
Money market funds		0		0
Mutual funds		0		0
Total trading securities		0		0
Securities available-for-sale:
U.S. treasury securities		1,999		0
U.S. agency securities		18,623		30,431
CMOs		546,475		534,156
MBSs		167,381		159,765
Municipal securities		381,554		423,820
CDOs		0		0
Corporate debt securities		0		1,802
Equity securities		3,516		3,261
Total available-for-sale securities		1,119,548		1,153,235
Mortgage servicing rights	[1]	0		0
Derivative assets	[1]	26,151		9,018
Liabilities:
Derivative liabilities	[2]	28,030		11,980
Level 3
Trading securities:
Money market funds		0		0
Mutual funds		0		0
Total trading securities		0		0
Securities available-for-sale:
U.S. treasury securities		0		0
U.S. agency securities		0		0
CMOs		0		0
MBSs		0		0
Municipal securities		0		0
CDOs		31,870		33,774
Corporate debt securities		0		0
Equity securities		0		0
Total available-for-sale securities		31,870		33,774
Mortgage servicing rights	[1]	1,798		1,728
Derivative assets	[1]	0		0
Liabilities:
Derivative liabilities	[2]	$ 0		$ 0

[1] Included in other assets in the Consolidated Statements of Financial Condition.

[2] Included in other liabilities in the Consolidated Statements of Financial Condition.