Fair Value (Detail) - Recurring Fair Value Measurements - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Trading securities:
Total trading securities		$ 16,894	$ 17,460
Securities available-for-sale:
CDOs		31,529	33,774	$ 18,309	$ 12,129
Total		1,306,636	1,187,009
Mortgage servicing rights		1,853	1,728	$ 1,893	$ 985
Level 1
Trading securities:
Money market funds		2,530	1,725
Mutual funds		14,364	15,735
Total trading securities		16,894	17,460
Securities available-for-sale:
U.S. treasury securities		16,980	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		16,980	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		0	0
U.S. agency securities		86,643	30,431
CMOs		687,185	534,156
MBSs		153,530	159,765
Municipal securities		327,570	423,820
CDOs		0	0
Corporate debt securities		0	1,802
Equity securities		3,199	3,261
Total		1,258,127	1,153,235
Mortgage servicing rights	[1]	0	0
Derivative assets	[1]	16,233	9,018
Liabilities:
Derivative liabilities	[2]	21,039	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		31,529	33,774
Corporate debt securities		0	0
Equity securities		0	0
Total		31,529	33,774
Mortgage servicing rights	[1]	1,853	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.