Fair Value Measurements (Valuation Techniques and Unobservable Inputs Used in the Valuation of Financial Instruments Falling within Level 3 of the Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Inputs Assets Quantitative Information [Line Items]
Total fair value of assets	$ 4,905,436	$ 4,615,508
Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	1.00%
Probability rate of default	0.00%
Loss severity	0.00%
Fair Value Inputs, Discount Rate	3.49%
Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	18.00%
Probability rate of default	4.38%
Loss severity	80.00%
Fair Value Inputs, Discount Rate	10.15%
Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	8.47%
Probability rate of default	0.98%
Loss severity	3.21%
Fair Value Inputs, Discount Rate	4.28%
Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	4.46%
Probability rate of default	0.00%
Loss severity	0.00%
Fair Value Inputs, Discount Rate	3.37%
Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	20.00%
Probability rate of default	4.05%
Loss severity	80.00%
Fair Value Inputs, Discount Rate	14.83%
Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	8.91%
Probability rate of default	1.45%
Loss severity	11.42%
Fair Value Inputs, Discount Rate	6.23%
Private label residential mortgage-backed securities and CMO's - Option-arm | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	2.86%
Probability rate of default	2.30%
Loss severity	6.31%
Fair Value Inputs, Discount Rate	5.11%
Private label residential mortgage-backed securities and CMO's - Option-arm | Discounted cash flow | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	2.99%
Probability rate of default	3.00%
Loss severity	17.01%
Fair Value Inputs, Discount Rate	38.85%
Private label residential mortgage-backed securities and CMO's - Option-arm | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value Inputs, Prepayment Rate	2.89%
Probability rate of default	2.83%
Loss severity	14.34%
Fair Value Inputs, Discount Rate	11.06%
Fair Value, Inputs, Level 3
Fair Value Inputs Assets Quantitative Information [Line Items]
Total fair value of assets	$ 145,419	$ 173,044
Fair Value, Inputs, Level 3 | Private label residential mortgage-backed securities and CMO's - Investment grade
Fair Value Inputs Assets Quantitative Information [Line Items]
Total fair value of assets	64,010
Fair Value, Inputs, Level 3 | Private label residential mortgage-backed securities and CMO's - Non-investment grade
Fair Value Inputs Assets Quantitative Information [Line Items]
Total fair value of assets	47,359
Fair Value, Inputs, Level 3 | Private label residential mortgage-backed securities and CMO's - Option-arm
Fair Value Inputs Assets Quantitative Information [Line Items]
Total fair value of assets	$ 29,514