Investments (Tables)

12 Months Ended

Dec. 31, 2013

Investments [Abstract]

Aggregate Values And Unrealized Gains And Losses Of Investment Securities

Investment securities as of December 31, 2013, and 2012, along with unrealized gains and losses determined on an individual security basis, are as follows:

	Cost		Gross unrealized gains		Gross unrealized losses		Fair value
	(dollars in thousands)
Investment securities available for sale
December 31, 2013
U.S. Treasury	$	373,223	$	259	$	45	$	373,437
Government agency	2,543,223		1,798		792		2,544,229
Mortgage-backed securities	2,486,297		4,526		43,950		2,446,873
Equity securities	543		21,604		—		22,147
State, county and municipal	186		1		—		187
Other	863		—		33		830
Total investment securities available for sale	$	5,404,335	$	28,188	$	44,820	$	5,387,703
December 31, 2012
U.S. Treasury	$	823,241	$	403	$	12	$	823,632
Government agency	3,052,040		3,501		337		3,055,204
Mortgage-backed securities	1,315,211		14,787		341		1,329,657
Equity securities	543		15,822		—		16,365
State, county and municipal	546		4		—		550
Other	838		—		18		820
Total investment securities available for sale	$	5,192,419	$	34,517	$	708	$	5,226,228
Investment securities held to maturity
December 31, 2013
Mortgage-backed securities	$	907	$	67	$	—	$	974
December 31, 2012
Mortgage-backed securities	$	1,342	$	133	$	27	$	1,448

Investment Securities Maturity Information

The following table provides the maturity distribution of amortizing investment securities. Repayments of mortgage-backed securities are dependent on the underlying loan balances. Equity securities do not have a stated maturity date.

	December 31, 2013				December 31, 2012
	Cost		Fair value		Cost		Fair value
	(dollars in thousands)
Investment securities available for sale
Amortizing securities maturing in:
One year or less	$	839,956	$	840,883	$	2,285,159	$	2,286,403
One through five years	2,077,539		2,077,800		1,590,608		1,592,923
Five through 10 years	—		—		898		880
Mortgage-backed securities	2,486,297		2,446,873		1,315,211		1,329,657
Equity securities	543		22,147		543		16,365
Total investment securities available for sale	$	5,404,335	$	5,387,703	$	5,192,419	$	5,226,228
Investment securities held to maturity
Mortgage-backed securities held to maturity	$	907	$	974	$	1,342	$	1,448

Securities Gains (Losses)

For each period presented, securities gains (losses) include the following:

	Year ended December 31
	2013		2012			2011
	(dollars in thousands)
Gross gains on sales of investment securities available for sale	$	—	$	2,324		$	531
Gross losses on sales of investment securities available for sale	—		(2		)	(793		)
Other than temporary impairment loss on equity securities	—		(45		)	(26		)
Total securities gains (losses)	$	—	$	2,277		$	(288	)

Investment Securities With Unrealized Losses

The following table provides information regarding securities with unrealized losses as of December 31, 2013, and 2012.

	Less than 12 months				12 months or more				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(dollars in thousands)
December 31, 2013
Investment securities available for sale:
U.S. Treasury	$	102,105	$	45	$	—	$	—	$	102,105	$	45
Government agency	780,552		761		29,969		31		810,521		792
Mortgage-backed securities	2,221,213		42,876		26,861		1,074		2,248,074		43,950
Other	830		33		—		—		830		33
Total	$	3,104,700	$	43,715	$	56,830	$	1,105	$	3,161,530	$	44,820
Investment securities held to maturity:
Mortgage-backed securities	$	—	$	—	$	—	$	—	$	—	$	—
December 31, 2012
Investment securities available for sale:
U.S. Treasury	$	120,045	$	12	$	—	$	—	$	120,045	$	12
Government agency	407,498		337		—		—		407,498		337
Mortgage-backed securities	135,880		214		9,433		127		145,313		341
Other	820		18		—		—		820		18
Total	$	664,243	$	581	$	9,433	$	127	$	673,676	$	708
Investment securities held to maturity:
Mortgage-backed securities	$	—	$	—	$	17	$	27	$	17	$	27