Parent Company Financial Statements - Consolidated Balance Sheet of Parent Company Only (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 02, 2011
Cash and cash equivalents	$ 213,981	$ 239,044	$ 208,953	$ 131,571
Securities available for sale	1,141,650	1,172,683	640,571
Other assets	350,867	344,729
Total assets	13,563,405	12,023,976	9,786,483
Other liabilities	130,418	163,151
Junior subordinated debt	75,205	204,019
Long-term	84,637	79,897
Total Liabilities	11,789,022	10,621,907
Stockholders' Equity	1,774,383	1,402,069	1,210,199	1,066,124
Total Liabilities and Stockholders' Equity	13,563,405	12,023,976
Parent Company [Member]
Cash and cash equivalents	145,910	114,654	166,058	91,560
Securities available for sale	2,061	1,962
Other assets	18,387	15,856
Total assets	2,180,033	1,940,822
Other liabilities	25,225	28,381
Advances from affiliates	294,245	295,100
Junior subordinated debt	76,290	205,156
Short-term	8,439	8,355
Long-term	1,451	1,761
Total Liabilities	405,650	538,753
Stockholders' Equity	1,774,383	1,402,069
Total Liabilities and Stockholders' Equity	2,180,033	1,940,822
Parent Company [Member] | Bank Subsidiary [Member]
Investment in and advances to subsidiaries	1,759,551	1,554,543
Parent Company [Member] | Non-bank Subsidiaries [Member]
Investment in and advances to subsidiaries	$ 254,124	$ 253,807