Borrowings - Components of Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Short-term Debt [Line Items]
Borrowings	$ 827,581	$ 237,084
Federal Home Loan Bank advances [Member]
Short-term Debt [Line Items]
Borrowings	500,000	148,000
Borrowings on secured lines of credit [Member]
Short-term Debt [Line Items]
Borrowings	269,400	30,000
Term Loans [Member]
Short-term Debt [Line Items]
Borrowings	$ 58,181	$ 59,084