Stock Compensation Plans and Other Employee Benefit Plans (Narrative) (Details)	1 Months Ended	12 Months Ended
	May. 31, 2012 shares	Dec. 31, 2015 USD ($) $ / shares Rate shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Jul. 31, 2015 shares	May. 31, 2015 shares	Dec. 31, 2012 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares		5,600,000
Allocated Share-based Compensation Expense		$ 9,700,000	$ 10,100,000	$ 6,700,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense		$ 3,800,000	4,000,000	$ 2,500,000
Allocated Sharebased Compensation Expense Modification Of Performance Measurement			$ 2,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares		$ 9.72	$ 11.52	$ 17.49
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		$ 2,500,000	$ 2,300,000	$ 1,200,000
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options		985,000	900,000	485,000
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options		11,700,000	5,900,000	15,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized		11,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value		7,900,000	7,800,000	7,400,000
Defined Contribution Plan, Employer Discretionary Contribution Amount		6,400,000	5,000,000	4,900,000
Pension Expense		$ 1,400,000	$ (1,100,000)	$ 0
Two Thousand And Fifteen Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 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 | shares		137,593	146,112	181,522			314,226
Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		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 | shares		276,533	295,679	307,512			214,565
Excess Tax Benefit Over Estimate		$ 517,000	$ 254,000	$ 329,000
Minimum | Two Thousand And Seven Plan And Two Thousand And Fifteen Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Minimum | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		1 year
Minimum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Performance Based Award Payouts | 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]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		5 years
Share Based Compensation By Share Based Payment Award Options Term		7 years
Maximum | Nineteen Ninety Seven Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation By Share Based Payment Award Options Term		10 years
Maximum | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		5 years
Maximum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation By Share Based Payment Award Options 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 | shares		503,000
HPK Financial Corporation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Number Of Participants		100
Defined Benefit Plan, Benefit Obligation		$ 6,100,000
Defined Benefit Plan, Fair Value of Plan Assets		$ 4,900,000
Diamond Bancorp, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Benefit Plan, Number Of Participants		35
Defined Benefit Plan, Benefit Obligation		$ 3,100,000
Defined Benefit Plan, Fair Value of Plan Assets		2,100,000
Cash Incentive And Retention Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense		0	20,000	115,000
Deferred Compensation Arrangement with Individual, Distributions Paid		100,000	$ 473,000	$ 0
Deferred Compensation, Cash Awards, Outstanding		$ 0
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		56,517	66,521	62,096
Employee Stock Purchase Plan, Compensation Expense		$ 0	$ 377,000	$ 355,000
Employee Stock Purchase Plan, Additional Shares Authorized | shares	300,000
Employee Stock Ownership Plan (ESOP), Number of Committed-to-be-Released Shares | shares		14,053
Employee Stock Ownership Plan (ESOP), Shares in ESOP | shares		135,982
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		20,475	19,488	30,547
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Additionally Authorized | shares					150,000
Deferred Compensation, Shares To Be Issued | shares		279,479
Deferred Compensation Arrangement with Individual, Common Stock Reserved for Future Issuance | shares		148,363
Granted in Two Thousand Fifteen | Maximum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Performance Based Award Payouts | Rate		150.00%
Granted in Two Thousand Fifteen | Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Performance Based Award Payouts | Rate		150.00%
Granted Prior To Two Thousand Fifteen | Maximum | Ltip Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage Of Performance Based Award Payouts | 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 Of Performance Based Award Payouts | Rate		200.00%