Loans (Details 7) (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2013
Allowance for loan losses
Balances at beginning of period	$ 53,563	$ 52,397	$ 63,285	$ 63,285
Total charge-offs	(1,637)	(1,551)	(5,589)
Total recoveries	1,538	2,717	881
Balances at end of period	53,464	53,563	58,577	53,563
Breakdown of allowance by specific valuation and general valuation allowance
Impaired loans	77,948	72,814		72,814
Specific valuation allowance	8,291	3,815		3,815
Coverage ratio (as a percent)	10.64%			5.24%
Non-impaired loans	2,801,945	2,751,892		2,751,892
General valuation allowance	45,173	49,748		49,748
Coverage ratio (as a percent)	1.61%			1.81%
Gross loans receivable	2,907,684	2,872,263	2,189,468	2,872,263
Total allowance for loan losses	53,464	53,563	58,577	53,563
Allowance coverage ratio (as a percent)	1.86%	1.90%		1.90%
Construction
Allowance for loan losses
Balances at beginning of period	814		453	453
Provision (credit) for losses on loans and loan commitments	(23)		241
Balances at end of period	791	814	694	814
Breakdown of allowance by specific valuation and general valuation allowance
Impaired loans		2,471		2,471
Coverage ratio (as a percent)	0.00%			0.00%
Non-impaired loans	43,277	37,896		37,896
General valuation allowance	791	814		814
Coverage ratio (as a percent)	1.83%			2.15%
Gross loans receivable	43,277	40,367		40,367
Total allowance for loan losses	791	814	694	814
Allowance coverage ratio (as a percent)	1.83%	2.02%		2.02%
Real Estate Secured
Allowance for loan losses
Balances at beginning of period	41,401		49,956	49,956
Total charge-offs	(672)		(4,405)
Total recoveries	1,028		215
Provision (credit) for losses on loans and loan commitments	(2,593)		(1,468)
Balances at end of period	39,164	41,401	44,298	41,401
Breakdown of allowance by specific valuation and general valuation allowance
Impaired loans	67,900	63,363		63,363
Specific valuation allowance	2,911	1,857		1,857
Coverage ratio (as a percent)	4.29%			2.93%
Non-impaired loans	2,333,303	2,268,758		2,268,758
General valuation allowance	36,253	39,544		39,544
Coverage ratio (as a percent)	1.55%			1.74%
Gross loans receivable	2,401,203	2,332,121		2,332,121
Total allowance for loan losses	39,164	41,401	44,298	41,401
Allowance coverage ratio (as a percent)	1.63%	1.78%		1.78%
Commercial & Industrial
Allowance for loan losses
Balances at beginning of period	11,238		12,737	12,737
Total charge-offs	(964)		(1,183)
Total recoveries	510		658
Provision (credit) for losses on loans and loan commitments	2,569		1,252
Balances at end of period	13,353	11,238	13,464	11,238
Breakdown of allowance by specific valuation and general valuation allowance
Impaired loans	10,048	6,980		6,980
Specific valuation allowance	5,380	1,958		1,958
Coverage ratio (as a percent)	53.54%			28.05%
Non-impaired loans	409,265	430,544		430,544
General valuation allowance	7,973	9,280		9,280
Coverage ratio (as a percent)	1.95%			2.16%
Gross loans receivable	419,313	437,524		437,524
Total allowance for loan losses	13,353	11,238	13,464	11,238
Allowance coverage ratio (as a percent)	3.18%	2.57%		2.57%
Consumer
Allowance for loan losses
Balances at beginning of period	110		139	139
Total charge-offs	(1)		(1)
Total recoveries			8
Provision (credit) for losses on loans and loan commitments	47		(25)
Balances at end of period	156	110	121	110
Breakdown of allowance by specific valuation and general valuation allowance
Coverage ratio (as a percent)	0.00%			0.00%
Non-impaired loans	16,100	14,694		14,694
General valuation allowance	156	110		110
Coverage ratio (as a percent)	0.97%			0.75%
Gross loans receivable	16,100	14,694		14,694
Total allowance for loan losses	$ 156	$ 110	$ 121	$ 110
Allowance coverage ratio (as a percent)	0.97%	0.75%		0.75%