Loans Receivable and Allowance for Loan Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 64,664	$ 70,348
Provision charged to operations	400	1,500
Recoveries of loans previously charged off	431	585
Loans charged off	(2,075)	(2,399)
Balance at end of period	63,420	70,034
Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	34,144	37,962
Provision charged to operations	(2,000)	(823)
Recoveries of loans previously charged off	67	229
Loans charged off	(741)	(975)
Balance at end of period	31,470	36,393
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	24,107	20,315
Provision charged to operations	1,330	3,853
Recoveries of loans previously charged off	243	113
Loans charged off	(519)	(780)
Balance at end of period	25,161	23,501
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	4,929	5,224
Provision charged to operations	144	(2)
Recoveries of loans previously charged off	121	243
Loans charged off	(815)	(644)
Balance at end of period	4,379	4,821
Total Portfolio Segments [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	63,180	63,501
Provision charged to operations	(526)	3,028
Recoveries of loans previously charged off	431	585
Loans charged off	(2,075)	(2,399)
Balance at end of period	61,010	64,715
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	1,484	6,847
Provision charged to operations	926	(1,528)
Recoveries of loans previously charged off	0	0
Loans charged off	0	0
Balance at end of period	$ 2,410	$ 5,319