Securities In An Unrealized Loss Position Securities In An Unrealized Loss Position (Narrative) (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	$ 3,656,084,000	$ 2,895,204,000
Gross Unrealized Losses	95,535,000	69,142,000
Available For Sale Equity Securities Gross Unrealized Gains	12,022,000	20,314,000
Loans and Leases Receivable, Other, Allowance	$ 2,000,000	3,000,000
Noninvestment Grade Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	8
Preferred stocks
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	$ 36,242,000	49,774,000
Gross Unrealized Losses	4,283,000	4,165,000
Available For Sale Equity Securities Gross Unrealized Gains	12,022,000	8,385,000
Common stocks
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	47,359,000	15,929,000
Gross Unrealized Losses	10,669,000	5,453,000
Available For Sale Equity Securities Gross Unrealized Gains	0	$ 11,929,000
Common stocks | Noninvestment Grade Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	83,600,000
Available For Sale Equity Securities Gross Unrealized Gains	$ 15,000,000