Fair Value Measurements - Financial instruments not carried at fair value (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposit liabilities	$ 1,194,815	$ 1,245,367
Notes payable and debt	2,726,917	1,662,580
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Assets	346,359	354,382
Deposit liabilities	1,194,815	1,245,367
Notes payable and debt	2,726,917	1,662,580
Financial Liabilities	3,921,732	2,907,947
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Assets	363,251	371,625
Deposit liabilities	1,471,562	1,543,761
Notes payable and debt	2,919,907	1,897,854
Financial Liabilities	$ 4,391,469	$ 3,441,615