Derivative Financial Instruments - Effect of Derivative Instruments on Consolidated Statements of Income and Comprehensive Income (Details) (Mortgage Banking Income, Nondesignated, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments Gain (Loss) [Line Items]
Gain (Loss) Included in Mortgage Banking Income	$ (971)	$ (15,711)	$ 6,723	$ 8,221
Treasury Options
Derivative Instruments Gain (Loss) [Line Items]
Gain (Loss) Included in Mortgage Banking Income	(2,580)	(641)	(1,525)	(7,597)
Treasury/Eurodollar futures
Derivative Instruments Gain (Loss) [Line Items]
Gain (Loss) Included in Mortgage Banking Income	(6)		100	4
Forward commitments to buy/sell loans/mortgage-backed securities
Derivative Instruments Gain (Loss) [Line Items]
Gain (Loss) Included in Mortgage Banking Income	$ 1,615	$ (15,070)	$ 8,148	$ 15,814