Investments and MBS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Amortized cost	$ 1,433,762,000		$ 1,452,258,000
AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	19,324,000		61,512,000
Available for sale	1,429,812,000		1,513,157,000
Amortized Cost	165,000		206,000
HeldToMaturitySecuritiesGrossUnrealizedGainAccumulatedInInvestments	0		0
Fair Value	165,000		206,000
Gain (Loss) on Investments [Abstract]
Proceeds from Sales	67,105,000		879,174,000	586,340,000
Gross Realized Gains	0		24,024,000	18,771,000
Gross Realized Losses	0		189,000	2,535,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Market Value	690,005,000		0
Market Value, Less than 12 months	(22,545,000)		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Market Value	12,947,000		12,921,000
Market Value, 12 months or longer	(729,000)		(613,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Market Value, Total	702,952,000		12,921,000
Market Value	(23,274,000)		(613,000)
Other-than-temporary impairment losses on securities	0	[1]	6,819,000	0	[1]
Held-to-maturity Securities, Debt Maturities [Abstract]
Amortized Cost, Due within one year	0
Amortized Cost, Due after one year through five years	0
Amortized Cost, Due afer five years through ten years	0
Amortized Cost, Due after ten years	165,000
Amortized Cost, Total	165,000		206,000
Estimated Fair Value, Due within one year	0
Estimated Fair Value, Due after one year through five years	0
Estimated Fair Value, Due after five years through ten years	0
Estimated Fair Value, Due after ten years	165,000
Fair Value	165,000		206,000
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Amortized Cost, Due within on year	0
Amortized Cost, Due after one year through five years	20,140,000
Amortized Cost, Due after five years through ten years	83,919,000
Amortized Cost, Due after ten years	1,329,703,000
Amortized Cost, Total	1,433,762,000
Estimated Fair Value, Due within one year	0
Estimated Fair Value, Due after one year through five years	20,395,000
Estimated Fair Value, Due after five years through ten years	83,539,000
Estimated Fair Value, Due after ten years	1,325,878,000
Available for sale	1,429,812,000		1,513,157,000
AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInInvestments	23,274,000		613,000
HeldToMaturitySecuritiesGrossUnrealizedLossesAccumulatedInInvestments	0		0
Gain (Loss) on Investments, Excluding Other than Temporary Impairments			2,500,000
MBS
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Amortized cost	1,248,908,000		1,263,786,000
AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	13,269,000		45,052,000
Available for sale	1,239,900,000		1,308,838,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Market Value	679,954,000		0
Market Value, Less than 12 months	(22,277,000)		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Market Value	0		0
Market Value, 12 months or longer	0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Market Value, Total	679,954,000		0
Market Value	(22,277,000)		0
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale	1,239,900,000		1,308,838,000
AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInInvestments	22,277,000		0
Municipal Bonds
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Amortized cost	184,642,000		188,467,000
AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	6,045,000		16,452,000
Available for sale	189,690,000		204,306,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Market Value	10,051,000		0
Market Value, Less than 12 months	(268,000)		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Market Value	12,947,000		12,921,000
Market Value, 12 months or longer	(729,000)		(613,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Market Value, Total	22,998,000		12,921,000
Market Value	(997,000)		(613,000)
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale	189,690,000		204,306,000
AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInInvestments	997,000		613,000
Tax credits
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Amortized Cost	165,000		206,000
HeldToMaturitySecuritiesGrossUnrealizedGainAccumulatedInInvestments	0		0
Fair Value	165,000		206,000
Held-to-maturity Securities, Debt Maturities [Abstract]
Fair Value	165,000		206,000
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
HeldToMaturitySecuritiesGrossUnrealizedLossesAccumulatedInInvestments	0		0
Other
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Amortized cost	212,000		5,000
AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	10,000		8,000
Available for sale	222,000		13,000
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Market Value	0		0
Market Value, Less than 12 months	0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Market Value	0		0
Market Value, 12 months or longer	0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Market Value, Total	0		0
Market Value	0		0
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Available for sale	222,000		13,000
AvailableForSaleSecuritiesGrossUnrealizedLossAccumulatedInInvestments	$ 0		$ 0

[1] The other-than-temporary impairment recognized in earnings during 2012 did not have a portion recognized in accumulated other comprehensive income.