Fair Value Measurements - Gains (Losses) from Loans Held-for-Sale (Details) - Loans Held For Sale - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	$ 7,936	$ 6,380	$ 30,363	$ 10,005
Interest income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	810	811	1,824	849
Change in fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	614	43	2,002	199
Net gain (loss) on sale of loans and other mortgage banking revenue
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	$ 6,512	$ 5,526	$ 26,537	$ 8,957