Investments (Tables)

12 Months Ended

Dec. 31, 2014

Investments [Abstract]

Aggregate Values And Unrealized Gains And Losses Of Investment Securities

December 31, 2014 and 2013, were as follows:

	December 31, 2014
(Dollars in thousands)	Cost		Gross unrealized gains		Gross unrealized losses		Fair value
Investment securities available for sale
U.S. Treasury	$	2,626,900	$	2,922	$	152	$	2,629,670
Government agency	908,362		702		247		908,817
Mortgage-backed securities	3,628,187		16,964		11,847		3,633,304
Municipal securities	125		1		—		126
Total investment securities available for sale	$	7,163,574	$	20,589	$	12,246	$	7,171,917
	December 31, 2013
	Cost		Gross unrealized gains		Gross unrealized losses		Fair value
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
Municipal securities	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, 2014
	Cost		Gross unrealized gains		Gross unrealized losses		Fair value
Investment securities held to maturity
Mortgage-backed securities	$	518	$	26	$	—	$	544
	December 31, 2013
	Cost		Gross unrealized gains		Gross unrealized losses		Fair value
Mortgage-backed securities	$	907	$	67	$	—	$	974

Investment Securities Maturity Information

The following table provides the amortized cost and fair value by contractual maturity. Expected maturities will differ from contractual maturities on certain securities because borrowers and issuers may have the right to call or prepay obligations with or without prepayment penalties. Repayments of mortgage-backed securities are dependent on the repayments of the underlying loan balances. Equity securities do not have a stated maturity date.

	December 31, 2014				December 31, 2013
(Dollars in thousands)	Cost		Fair value		Cost		Fair value
Investment securities available for sale
Non-amortizing securities maturing in:
One year or less	$	447,866	$	447,992	$	839,956	$	840,883
One through five years	3,087,521		3,090,621		2,077,539		2,077,800
Mortgage-backed securities	3,628,187		3,633,304		2,486,297		2,446,873
Equity securities	—		—		543		22,147
Total investment securities available for sale	$	7,163,574	$	7,171,917	$	5,404,335	$	5,387,703
Investment securities held to maturity
Mortgage-backed securities held to maturity	$	518	$	544	$	907	$	974

Securities Gains (Losses)

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

	Year ended December 31
(Dollars in thousands)	2014			2013		2012
Gross gains on retirement/sales of investment securities available for sale	$	29,129		$	—	$	2,324
Gross losses on sales of investment securities available for sale	(33		)	—		(2		)
Other than temporary impairment loss on equity securities	—			—		(45		)
Total securities gains	$	29,096		$	—	$	2,277

Investment Securities With Unrealized Losses

The following table provides information regarding securities with unrealized losses as of December 31, 2014 and 2013.

	December 31, 2014
	Less than 12 months				12 months or more				Total
(Dollars in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Investment securities available for sale:
U.S. Treasury	$	338,612	$	151	$	1,015	$	1	$	339,627	$	152
Government agency	261,288		247		—		—		261,288		247
Mortgage-backed securities	573,374		1,805		831,405		10,042		1,404,779		11,847
Total	$	1,173,274	$	2,203	$	832,420	$	10,043	$	2,005,694	$	12,246
	December 31, 2013
	Less than 12 months				12 months or more				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
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