Investment Securities (Details 3) (USD $)	9 Months Ended
	Sep. 30, 2013 security	Dec. 31, 2012
Investment securities in an unrealized loss position
Available-for-Sale, Less Than 12 Months, Fair Value	$ 831,918,000	$ 343,903,000
Available For Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(26,924,000)	(2,223,000)
Available-for-Sale, 12 Months or Longer, Fair Value	11,680,000	22,953,000
Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(647,000)	(238,000)
Available-for-Sale, Total Fair Value	843,598,000	366,856,000
Available For Sale Securities Gross Unrealized Losses	27,571,000	2,461,000
Held-to-Maturity, Less Than 12 Months, Fair Value	2,161,327,000	351,762,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(61,487,000)	(1,366,000)
Held-to-Maturity, 12 Months or Longer, Fair Value	19,891,000	0
Held-to-Maturity, 12 Months or Longer, Gross Unrealized Losses	(290,000)	0
Held-to-Maturity, Total Fair Value	2,181,218,000	351,762,000
Held-to-Maturity, Gross Unrealized Losses	61,777,000	1,366,000
Number of investment securities that were in an unrealized loss position	243
Municipal debt securities issued by a single state or political subdivision as a percentage of total fair value of entire municipal debt securities threshold	5.00%
Debt Securities Issued by the U.S. Treasury and Government Agencies
Investment securities in an unrealized loss position
Available-for-Sale, Less Than 12 Months, Fair Value	18,693,000	2,295,000
Available For Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(181,000)	(14,000)
Available-for-Sale, 12 Months or Longer, Fair Value	2,149,000	564,000
Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(10,000)	(3,000)
Available-for-Sale, Total Fair Value	20,842,000	2,859,000
Available For Sale Securities Gross Unrealized Losses	191,000	17,000
Held-to-Maturity, Less Than 12 Months, Fair Value	183,850,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(1,947,000)
Held-to-Maturity, 12 Months or Longer, Fair Value	0
Held-to-Maturity, 12 Months or Longer, Gross Unrealized Losses	0
Held-to-Maturity, Total Fair Value	183,850,000
Held-to-Maturity, Gross Unrealized Losses	1,947,000	0
Debt Securities Issued by States and Political Subdivisions
Investment securities in an unrealized loss position
Available-for-Sale, Less Than 12 Months, Fair Value	340,491,000	72,400,000
Available For Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(11,337,000)	(955,000)
Available-for-Sale, 12 Months or Longer, Fair Value	114,000	0
Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(1,000)	0
Available-for-Sale, Total Fair Value	340,605,000	72,400,000
Available For Sale Securities Gross Unrealized Losses	11,338,000	955,000
Held-to-Maturity, Less Than 12 Months, Fair Value	8,105,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(22,000)
Held-to-Maturity, 12 Months or Longer, Fair Value	0
Held-to-Maturity, 12 Months or Longer, Gross Unrealized Losses	0
Held-to-Maturity, Total Fair Value	8,105,000
Held-to-Maturity, Gross Unrealized Losses	22,000
Debt Securities Issued by Corporations
Investment securities in an unrealized loss position
Available-for-Sale, Less Than 12 Months, Fair Value	201,817,000
Available For Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(6,396,000)
Available-for-Sale, 12 Months or Longer, Fair Value	0
Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0
Available-for-Sale, Total Fair Value	201,817,000
Available For Sale Securities Gross Unrealized Losses	6,396,000
Held-to-Maturity, Less Than 12 Months, Fair Value	151,775,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(3,731,000)
Held-to-Maturity, 12 Months or Longer, Fair Value	0
Held-to-Maturity, 12 Months or Longer, Gross Unrealized Losses	0
Held-to-Maturity, Total Fair Value	151,775,000
Held-to-Maturity, Gross Unrealized Losses	3,731,000	0
Mortgage-Backed Securities
Investment securities in an unrealized loss position
Available-for-Sale, Less Than 12 Months, Fair Value	270,917,000	269,208,000
Available For Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(9,010,000)	(1,254,000)
Available-for-Sale, 12 Months or Longer, Fair Value	9,417,000	22,389,000
Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(636,000)	(235,000)
Available-for-Sale, Total Fair Value	280,334,000	291,597,000
Available For Sale Securities Gross Unrealized Losses	9,646,000	1,489,000
Held-to-Maturity, Less Than 12 Months, Fair Value	1,817,597,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(55,787,000)
Held-to-Maturity, 12 Months or Longer, Fair Value	19,891,000
Held-to-Maturity, 12 Months or Longer, Gross Unrealized Losses	(290,000)
Held-to-Maturity, Total Fair Value	1,837,488,000
Held-to-Maturity, Gross Unrealized Losses	56,077,000	1,366,000
Residential - Government Agencies
Investment securities in an unrealized loss position
Available-for-Sale, Less Than 12 Months, Fair Value	54,834,000	7,325,000
Available For Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(382,000)	(57,000)
Available-for-Sale, 12 Months or Longer, Fair Value	9,417,000	22,389,000
Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(636,000)	(235,000)
Available-for-Sale, Total Fair Value	64,251,000	29,714,000
Available For Sale Securities Gross Unrealized Losses	1,018,000	292,000
Held-to-Maturity, Less Than 12 Months, Fair Value	1,577,637,000	351,762,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(53,289,000)	(1,366,000)
Held-to-Maturity, 12 Months or Longer, Fair Value	0	0
Held-to-Maturity, 12 Months or Longer, Gross Unrealized Losses	0	0
Held-to-Maturity, Total Fair Value	1,577,637,000	351,762,000
Held-to-Maturity, Gross Unrealized Losses	53,289,000	1,366,000
Commercial - Government Agencies
Investment securities in an unrealized loss position
Available-for-Sale, Less Than 12 Months, Fair Value	216,083,000	261,883,000
Available For Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(8,628,000)	(1,197,000)
Available-for-Sale, 12 Months or Longer, Fair Value	0	0
Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0	0
Available-for-Sale, Total Fair Value	216,083,000	261,883,000
Available For Sale Securities Gross Unrealized Losses	8,628,000	1,197,000
Held-to-Maturity, Less Than 12 Months, Fair Value	239,960,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(2,498,000)
Held-to-Maturity, 12 Months or Longer, Fair Value	19,891,000
Held-to-Maturity, 12 Months or Longer, Gross Unrealized Losses	(290,000)
Held-to-Maturity, Total Fair Value	259,851,000
Held-to-Maturity, Gross Unrealized Losses	2,788,000
Hawaii | Debt Securities Issued by States and Political Subdivisions
Investment securities in an unrealized loss position
Investments securities at fair value	$ 567,500,000
Municipal Debt Securities | Geographic Concentration Risk | Hawaii | Debt Securities Issued by States and Political Subdivisions
Investment securities in an unrealized loss position
Concentration risk percentage	67.00%
Hawaiian Municipal Debt Securities [Member] | Investment Concentration Risk [Member] | Hawaii | General Obligation Bond [Member]
Investment securities in an unrealized loss position
Concentration risk percentage	76.00%
Moody's, Aa2 or Better Rating [Member] | Hawaiian Municipal Debt Securities [Member] | Investment Concentration Risk [Member] | Hawaii | Debt Securities Issued by States and Political Subdivisions
Investment securities in an unrealized loss position
Concentration risk percentage	94.00%