Notes Payable: Notes Payable (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revolving Credit Facility [Line Items]
Balance Outstanding	$ 75,000,000	$ 82,500,000
Deferred Finance Costs [Abstract]
Write off of Deferred Debt Issuance Cost			1,500,000
Revolving Credit Facility [Member]
Revolving Credit Facility [Line Items]
Balance Outstanding	75,000,000	82,500,000
Current Borrowing Capacity	500,000,000
Expiration Date	May 29, 2019
Maximum Borrowing Capacity	750,000,000
Commitment Fee Percentage	0.175%
Commitment Fee Percentage Decrease	0.025%
Letters of Credit Outstanding	35,000,000	22,000,000
Deferred Finance Costs [Abstract]
Deferred Finance Costs, Noncurrent, Gross	3,800,000
Deferred Finance Costs, Noncurrent, Net	1,779,000
Amortization Expense for Deferred Financing Costs	$ 616,000	$ 752,000	$ 2,187,000
Debt Covenants Disclosure [Abstract]
Covenant Requirement - Recourse Leverage Ratio, Actual	55.00%
Covenant Requirement - Recourse Leverage Ratio, Maximum	65.00%
Revolving Credit Facility [Member] | Base Rate Borrowings [Member]
Revolving Credit Facility [Line Items]
Interest Rate at Period End	0.125%
Interest Rate Decrease	0.25%
Revolving Credit Facility [Member] | Eurodollar Borrowings [Member]
Revolving Credit Facility [Line Items]
Interest Rate at Period End	1.125%
Interest Rate Decrease	0.25%
Revolving Credit Facility [Member] | Letters of Credit [Member]
Revolving Credit Facility [Line Items]
Interest Rate at Period End	1.125%
Interest Rate Decrease	0.25%