Stock Compensation Plans and Other Employee Benefit Plans (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares Rate shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	May 31, 2015 shares	Dec. 31, 2013 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares) | shares	4,600,000
Allocated Share-based Compensation Expense	$ 9,300,000	$ 9,700,000	$ 10,100,000
Tax benefit	3,700,000	$ 3,800,000	$ 4,000,000
Modification expense	$ 2,100,000
Grants in period fair value (in dollars per share) | $ / shares	$ 8.61	$ 9.72	$ 11.52
Fair value granted	$ 5,800,000	$ 2,500,000	$ 2,300,000
Tax benefit realized	2,300,000	985,000	900,000
Cash received from exercise	11,800,000	11,700,000	5,900,000
Unrecognized compensation	11,000,000
Fair value vested	8,400,000	7,900,000	7,800,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	6,600,000	6,400,000	5,000,000
Pension Expense	$ 526,000	$ 1,400,000	$ (1,100,000)
Two Thousand And Fifteen Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares) | shares				5,485,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that could be issued based on the grants made to date (in shares) | shares	133,425	137,593	146,112		181,522
Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	3 years
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Awards Paid In Performance Shares		17.00%
Maximum number of shares that could be issued based on the grants made to date (in shares) | shares	298,180	276,533	295,679		307,512
Excess Tax Benefit Over Estimate	$ 241,000	$ 517,000	$ 254,000
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	95.00%	90.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans | shares	50,920	56,517	66,521
Employee Stock Purchase Plan, Compensation Expense	$ 0	$ 0	$ 377,000
Employee Stock Ownership Plan (ESOP), Number of Committed-to-be-Released Shares | shares	9,046
Employee Stock Ownership Plan (ESOP), Shares in ESOP | shares	85,062
Minimum | Two Thousand And Seven Plan And Two Thousand And Fifteen Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	3 years
Minimum | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	1 year
Minimum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage award payout | Rate	0.00%
Maximum | Two Thousand And Seven Plan And Two Thousand And Fifteen Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	5 years
Option term	7 years
Maximum | Nineteen Ninety Seven Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option term	10 years
Maximum | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period (in shares)	5 years
Maximum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option term	7 years
Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that could be issued based on the grants made to date (in shares) | shares	485,000
HPK Financial Corporation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Number Of Participants	42
Defined Benefit Plan, Benefit Obligation	$ 5,400,000
Defined Benefit Plan, Fair Value of Plan Assets	$ 3,400,000
Diamond Bancorp, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Number Of Participants	23
Defined Benefit Plan, Benefit Obligation	$ 2,500,000
Defined Benefit Plan, Fair Value of Plan Assets	2,000,000
Cash Incentive And Retention Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense	0	0	20,000
Deferred Compensation Arrangement with Individual, Distributions Paid	0	$ 100,000	$ 473,000
Deferred Compensation, Cash Awards, Outstanding	$ 0
Directors Deferred Fee And Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Shares Issued | shares	25,362	20,475	19,488
Deferred Compensation, Shares To Be Issued | shares	286,094
Deferred Compensation Arrangement with Individual, Common Stock Reserved for Future Issuance | shares	116,386
Granted in Two Thousand Fifteen | Maximum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage award payout | Rate	150.00%
Granted in Two Thousand Fifteen | Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage award payout | Rate	150.00%
Granted Prior To Two Thousand Fifteen | Maximum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage award payout | Rate	200.00%
Granted in Two Thousand and Thirteen and Two Thousand and Fourteen | Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage award payout | Rate	200.00%