Securities (Tables)

12 Months Ended

Dec. 31, 2011

Securities [Abstract]

Amortized cost and fair value of securities

	December 31, 2011								December 31, 2010
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury	$	150	$	14	$	—		164	$	10,797	$	52	$	5		10,844
U.S. government agencies		248,595		1,308		—		249,903		106,054		971		434		106,591
Municipal obligations		294,489		15,218		42		309,665		181,747		4,107		5,411		180,443
Mortgage-backed securities		2,422,891		58,150		696		2,480,345		761,704		38,032		50		799,686
CMOs		1,426,495		21,774		2,193		1,446,076		367,662		6,880		2,491		372,051
Other debt securities		4,517		11		34		4,494		14,329		999		43		15,285
Other equity securities		4,208		2,086		41		6,253		3,428		660		103		3,985
	$	4,401,345	$	98,561	$	3,006	$	4,496,900	$	1,445,721	$	51,701	$	8,537	$	1,488,885

Amortized cost and fair value of securities by contractual maturity

	Amortized Cost		Fair Value
Due in one year or less	$	292,434	$	293,803
Due after one year through five years		915,985		934,279
Due after five years through ten years		405,288		421,935
Due after ten years		2,783,430		2,840,630
Equity securities		4,208		6,253
Total available for sale securities	$	4,401,345	$	4,496,900

Available for sale securities unrealized losses

	Losses < 12 months				Losses 12 months or >				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Treasury	$	—	$	—	$	—	$	—	$	—	$	—
U.S. government agencies		—		—		—		—		—		—
Municipal obligations		18,854		42		—		—		18,854		42
Mortgage-backed securities		212,900		692		337		4		213,237		696
CMOs		296,860		2,193		—		—		296,860		2,193
Other debt securities		398		34		—		—		398		34
Equity securities		1,685		39		2		2		1,687		41
	$	530,697	$	3,000	$	339	$	6	$	531,036	$	3,006

	Losses < 12 months				Losses 12 months or >				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S Treasury	$	9,980	$	5	$	—	$	—	$	9,980	$	5
U.S. government agencies		74,566		434		—		—		74,566		434
Municipal obligations		57,713		3,092		19,870		2,319		77,583		5,411
Mortgage-backed securities		122		1		1,340		49		1,462		50
CMOs		122,312		2,491		—		—		122,312		2,491
Other debt securities		379		6		459		37		838		43
Equity securities		2,552		87		11		16		2,563		103
	$	267,624	$	6,116	$	21,680	$	2,421	$	289,304	$	8,537