Dispositions and Held-for-Sale (Dispositions) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Mar. 17, 2018 USD ($) banking_branch
Disposition [Line Items]
Net gain on sale of business	$ 0	$ 0	$ 31,470	$ 0
Desert Community Bank
Disposition [Line Items]
Net cash payment in sale of branches			499,900
Net gain on sale of business			$ 31,500
Desert Community Bank | California
Disposition [Line Items]
Number of branches sold | banking_branch					8
Loans | Desert Community Bank
Disposition [Line Items]
Branch assets sold					$ 59,100
Cash and cash equivalents | Desert Community Bank
Disposition [Line Items]
Branch assets sold					9,000
Premises and equipment | Desert Community Bank
Disposition [Line Items]
Branch assets sold					7,900
Deposits | Desert Community Bank
Disposition [Line Items]
Branch liabilities sold					$ 613,700