Fair Value Measurements, Financial Instruments (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 2,140,326,000	$ 1,956,923,000
Investment securities	331,466,000	355,187,000
Available for sale securities	9,025,198,000	8,857,120,000
Fair value option securities	707,994,000	283,235,000
Residential mortgage loans held for sale	160,157,000	149,221,000
Loans	21,758,980,000	21,656,730,000
Allowance for loan losses	(205,340,000)	(207,457,000)	$ (223,967,000)	$ (230,682,000)
Loans, net of allowance	21,553,640,000	21,449,273,000
Mortgage servicing rights	238,193,000	259,254,000	274,978,000	252,867,000
Derviative contracts, net of cash collateral, Assets, Fair value	359,223,000	320,929,000
Time deposits	2,198,389,000	2,113,380,000
Subordinated debentures	275,880,000	275,913,000
Derivative contracts, net of cash collateral, Liabilities, Fair Value	299,698,000	362,306,000
Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,961,975,000	13,636,078,000
Allowance for loan losses	(103,577,000)	(102,226,000)	(120,083,000)	(124,269,000)
Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,600,651,000	4,764,813,000
Allowance for loan losses	(58,134,000)	(60,026,000)	(57,070,000)	(56,621,000)
Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,192,620,000	2,230,033,000
Allowance for loan losses	(15,668,000)	(17,964,000)	(18,431,000)	(18,451,000)
Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,003,734,000	1,025,806,000
Allowance for loan losses	(8,783,000)	(9,473,000)	$ (8,408,000)	$ (9,124,000)
U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	51,576,000	63,765,000
Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,952,742,000	1,791,584,000
Investment securities	12,106,000	12,612,000
Available for sale securities	6,040,086,000	5,804,708,000
Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	50,637,000	34,507,000
Investment securities	126,544,000	137,296,000
Available for sale securities	2,447,000	2,864,000
U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	1,878,000	493,000
Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	47,958,000	59,736,000
Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,932,357,000	2,953,889,000
Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	44,481,000	24,411,000
Investment securities	192,816,000	205,279,000
Available for sale securities	472,000	35,430,000
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	718,297,000	741,749,000
Interest-bearing cash and cash equivalents	564,404,000	401,675,000
Trading securities	2,140,326,000	1,956,923,000
Investment securities	331,466,000	355,187,000
Available for sale securities	9,025,198,000	8,857,120,000
Residential mortgage loans held for sale	160,157,000	149,221,000
Loans	21,758,980,000	21,656,730,000
Allowance for loan losses	(205,340,000)	(207,457,000)
Loans, net of allowance	21,553,640,000	21,449,273,000
Mortgage servicing rights	238,193,000	259,254,000
Derviative contracts, net of cash collateral, Assets, Fair value	359,223,000	320,929,000
Deposits with no stated maturity	23,133,413,000	23,150,383,000
Time deposits	2,198,389,000	2,113,380,000
Other borrowed funds	8,780,766,000	7,142,801,000
Subordinated debentures	275,880,000	275,913,000
Derivative contracts, net of cash collateral, Liabilities, Fair Value	299,698,000	362,306,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,961,975,000	13,636,078,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,600,651,000	4,764,813,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,192,620,000	2,230,033,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,003,734,000	1,025,806,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	51,576,000	63,765,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,952,742,000	1,791,584,000
Investment securities	12,106,000	12,612,000
Available for sale securities	6,040,086,000	5,804,708,000
Fair value option securities	707,994,000	283,235,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	50,637,000	34,507,000
Investment securities	126,544,000	137,296,000
Available for sale securities	2,447,000	2,864,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	40,890,000	42,656,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	44,481,000	24,411,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	1,878,000	493,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	47,958,000	59,736,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,932,357,000	2,953,889,000
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	192,816,000	205,279,000
Available for sale securities	472,000	35,430,000
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	718,297,000	741,749,000
Interest-bearing cash and cash equivalents	564,404,000	401,675,000
Trading securities	2,140,326,000	1,956,923,000
Investment securities	348,488,000	367,298,000
Available for sale securities	9,025,198,000	8,857,120,000
Residential mortgage loans held for sale	160,157,000	149,221,000
Loans	21,674,065,000	21,478,228,000
Allowance for loan losses	0	0
Loans, net of allowance	21,674,065,000	21,478,228,000
Mortgage servicing rights	238,193,000	259,254,000
Derviative contracts, net of cash collateral, Assets, Fair value	359,223,000	320,929,000
Deposits with no stated maturity	23,133,413,000	23,150,383,000
Time deposits	2,181,872,000	2,073,538,000
Other borrowed funds	8,750,845,000	7,071,953,000
Subordinated debentures	273,656,000	261,977,000
Derivative contracts, net of cash collateral, Liabilities, Fair Value	299,698,000	362,306,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,886,769,000	13,526,162,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,589,189,000	4,713,747,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,196,914,000	2,213,951,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,001,193,000	1,024,368,000
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	51,576,000	63,765,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,952,742,000	1,791,584,000
Investment securities	12,388,000	12,770,000
Available for sale securities	6,040,086,000	5,804,708,000
Fair value option securities	707,994,000	283,235,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	50,637,000	34,507,000
Investment securities	129,072,000	138,562,000
Available for sale securities	2,447,000	2,864,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	40,890,000	42,656,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	44,481,000	24,411,000
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	1,878,000	493,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	47,958,000	59,736,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,932,357,000	2,953,889,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	207,028,000	215,966,000
Available for sale securities	472,000	35,430,000
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	718,297,000	741,749,000
Interest-bearing cash and cash equivalents	564,404,000	401,675,000
Trading securities	0	0
Investment securities	0	0
Available for sale securities	1,878,000	493,000
Residential mortgage loans held for sale	0	0
Loans	0	0
Allowance for loan losses	0	0
Loans, net of allowance	0	0
Mortgage servicing rights	0	0
Derviative contracts, net of cash collateral, Assets, Fair value	4,720,000	44,074,000
Deposits with no stated maturity	0	0
Time deposits	0	0
Other borrowed funds	0	0
Subordinated debentures	0	0
Derivative contracts, net of cash collateral, Liabilities, Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities	0	0
Available for sale securities	0	0
Fair value option securities	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities	0	0
Available for sale securities	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	1,878,000	493,000
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0	0
Available for sale securities	0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Interest-bearing cash and cash equivalents	0	0
Trading securities	2,140,326,000	1,956,923,000
Investment securities	149,669,000	159,237,000
Available for sale securities	9,022,848,000	8,856,155,000
Residential mortgage loans held for sale	144,381,000	134,014,000
Loans	0	0
Allowance for loan losses	0	0
Loans, net of allowance	0	0
Mortgage servicing rights	0	0
Derviative contracts, net of cash collateral, Assets, Fair value	354,503,000	276,855,000
Deposits with no stated maturity	0	0
Time deposits	0	0
Other borrowed funds	0	0
Subordinated debentures	273,656,000	261,977,000
Derivative contracts, net of cash collateral, Liabilities, Fair Value	299,698,000	362,306,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	51,576,000	63,765,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	1,952,742,000	1,791,584,000
Investment securities	12,388,000	12,770,000
Available for sale securities	6,040,086,000	5,804,708,000
Fair value option securities	707,994,000	283,235,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	50,637,000	34,507,000
Investment securities	129,072,000	138,562,000
Available for sale securities	2,447,000	2,864,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	40,890,000	42,656,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	44,481,000	24,411,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	47,958,000	59,736,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	2,932,357,000	2,953,889,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	8,209,000	7,905,000
Available for sale securities	0	34,958,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Interest-bearing cash and cash equivalents	0	0
Trading securities	0	0
Investment securities	198,819,000	208,061,000
Available for sale securities	472,000	472,000
Residential mortgage loans held for sale	15,776,000	15,207,000
Loans	21,674,065,000	21,478,228,000
Allowance for loan losses	0	0
Loans, net of allowance	21,674,065,000	21,478,228,000
Mortgage servicing rights	238,193,000	259,254,000
Derviative contracts, net of cash collateral, Assets, Fair value	0	0
Deposits with no stated maturity	23,133,413,000	23,150,383,000
Time deposits	2,181,872,000	2,073,538,000
Other borrowed funds	8,750,845,000	7,071,953,000
Subordinated debentures	0	0
Derivative contracts, net of cash collateral, Liabilities, Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	13,886,769,000	13,526,162,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial real estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	4,589,189,000	4,713,747,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential mortgage [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	2,196,914,000	2,213,951,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Personal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans	1,001,193,000	1,024,368,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. government agency debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities	0	0
Available for sale securities	0	0
Fair value option securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Municipal and other tax-exempt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities	0	0
Available for sale securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Asset-backed securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other trading securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Residential non-agency mortgage-backed securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale securities	0	0
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Other debt securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	198,819,000	208,061,000
Available for sale securities	$ 472,000	$ 472,000