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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 63,420	$ 70,034	$ 64,664	$ 70,348
Provision charged to operations	1,500	1,000	1,900	2,500
Recoveries of loans previously charged off	1,117	577	1,548	1,162
Loans charged off	(2,162)	(4,606)	(4,237)	(7,005)
Balance at end of period	63,875	67,005	63,875	67,005
Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	31,470	36,393	34,144	37,962
Provision charged to operations	646	(2,789)	(1,354)	(3,611)
Recoveries of loans previously charged off	90	115	157	343
Loans charged off	(1,166)	(3,049)	(1,907)	(4,024)
Balance at end of period	31,040	30,670	31,040	30,670
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	25,161	23,501	24,107	20,315
Provision charged to operations	1,663	396	2,994	4,248
Recoveries of loans previously charged off	298	199	541	313
Loans charged off	(43)	(286)	(563)	(1,066)
Balance at end of period	27,079	23,810	27,079	23,810
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	4,379	4,821	4,929	5,224
Provision charged to operations	226	660	369	658
Recoveries of loans previously charged off	729	263	850	506
Loans charged off	(953)	(1,271)	(1,767)	(1,915)
Balance at end of period	4,381	4,473	4,381	4,473
Total Portfolio Segments [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	61,010	64,715	63,180	63,501
Provision charged to operations	2,535	(1,733)	2,009	1,295
Recoveries of loans previously charged off	1,117	577	1,548	1,162
Loans charged off	(2,162)	(4,606)	(4,237)	(7,005)
Balance at end of period	62,500	58,953	62,500	58,953
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	2,410	5,319	1,484	6,847
Provision charged to operations	(1,035)	2,733	(109)	1,205
Recoveries of loans previously charged off	0	0	0	0
Loans charged off	0	0	0	0
Balance at end of period	$ 1,375	$ 8,052	$ 1,375	$ 8,052