Loans Receivable - Summary of Changes in Accretable Yields of Acquired Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 354,892	$ 356,393
Acquisition	2,465
Transfers from nonaccretable difference to accretable yield	6,461	18,522
Accretion	(28,305)	(51,780)
Changes in expected cash flows not affecting nonaccretable differences	495	73,473
Balance at end of period	336,008	396,608
Acquired Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	78,349	76,623
Acquisition	929
Transfers from nonaccretable difference to accretable yield	1,515	2,042
Accretion	(2,237)	(6,499)
Changes in expected cash flows not affecting nonaccretable differences	(6,097)	8,973
Balance at end of period	72,459	81,139
Acquired Performing Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	276,543	279,770
Acquisition	1,536
Transfers from nonaccretable difference to accretable yield	4,946	16,480
Accretion	(26,068)	(45,281)
Changes in expected cash flows not affecting nonaccretable differences	6,592	64,500
Balance at end of period	$ 263,549	$ 315,469