Organization and Summary of Significant Accounting Policies - Correction of Immaterial Error (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Correction of an Immaterial Error to the Financial Statements
Service charges on deposit accounts	$ (7,955)	$ (9,381)
Credit and debit card fees	15,497	16,305
Occupancy expense	6,484	5,709
Card rewards program expense	5,718	5,775
Net income	$ 67,958	56,740
Restatement adjustment | Misclassifications of noninterest income and noninterest expense
Correction of an Immaterial Error to the Financial Statements
Service charges on deposit accounts		100
Credit and debit card fees		1,800
Occupancy expense		400
Card rewards program expense		1,300
Net income		$ 0