Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	$ 175,710		$ 173,783
Loans held for sale	351,467		201,012
Mortgage servicing rights	220,371		227,297
Mortgage-Related Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,771		19,700
Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	156,939		154,083
GSE certificates | Mortgage-Related Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,771	[1]	19,700
Municipal bonds | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	940		942
Capital trust notes | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	11,004		11,482
Preferred stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	126,303		123,011
Mutual Funds and Common Stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,692	[2]	18,648
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	175,710		173,783
Loans held for sale	351,467		379,399
Mortgage servicing rights	220,371		227,297
Interest rate lock commitments	8,862		4,397
Derivative assets-other	7,685	[3]	3,886	[4]
Derivative liabilities	(2,197)		(512)
Fair Value, Measurements, Recurring | Mortgage-Related Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,771		19,700
Fair Value, Measurements, Recurring | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	156,939		154,083
Fair Value, Measurements, Recurring | GSE certificates | Mortgage-Related Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,771		19,700
Fair Value, Measurements, Recurring | Municipal bonds | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	940		942
Fair Value, Measurements, Recurring | Capital trust notes | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	11,004		11,482
Fair Value, Measurements, Recurring | Preferred stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	126,303		123,011
Fair Value, Measurements, Recurring | Mutual Funds and Common Stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,692		18,648
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	114,897		112,035
Derivative assets-other	6,004	[3]	2,655	[4]
Derivative liabilities	(64)		(346)
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	114,897		112,035
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Preferred stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	97,793		95,051
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual Funds and Common Stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	17,104		16,984
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	60,813		61,748
Loans held for sale	351,467		379,399
Derivative assets-other	4,464	[3]	8,429	[4]
Derivative liabilities	(8,180)		(7,862)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Mortgage-Related Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,771		19,700
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	42,042		42,048
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | GSE certificates | Mortgage-Related Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	18,771		19,700
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Municipal bonds | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	940		942
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Capital trust notes | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	11,004		11,482
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Preferred stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	28,510		27,960
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Mutual Funds and Common Stock | Other Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds and common stock	1,588		1,664
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	220,371		227,297
Interest rate lock commitments	8,862		4,397
Fair Value, Measurements, Recurring | Netting Adjustment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets-other	(2,783)	[3],[5]	(7,198)	[4],[5]
Derivative liabilities	$ 6,047	[5]	$ 7,696	[5]

[1] Government-sponsored enterprise

[2] Primarily consists of mutual funds that are Community Reinvestment Act-qualified investments

[3] Includes $4.1 million to purchase Treasury options.

[4] Includes $2.6 million to purchase Treasury options.

[5] Includes cash collateral received from, and paid to, counterparties.