Investment (Held-to-Maturity) Securities (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2016 USD ($)		Dec. 31, 2015 USD ($)
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		$ 546,145		$ 597,724
Investment Securities, Debt Maturities, Carrying Value		546,145		597,836
Investment Securities, Fair Value		565,493		629,159
Investment Securities, Gross Unrealized Gain		21,154	[1]	31,687	[2]
Investment Securities, Gross Unrealized Loss		(1,806)	[1]	(364)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Carrying Value		546,145		597,836
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Fair Value		$ 565,493		629,159
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Nominal Yield		3.56%
Investment Securities, Pledged as Collateral [Abstract]
Investment Securities, Pledged as Collateral, Carrying Value		$ 322,208		231,033
Investment Securities, Pledged as Collateral, Fair Value		$ 323,808		$ 234,382
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		193		85
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 236,070		$ 133,934
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		5,188		15,095
Investment Securities, Continuous Unrealized Loss Position, Fair Value		241,258		149,029
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1,709		269
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		97		95
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		1,806		364
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value		334,115
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value		350,475
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value		6,028
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value		6,037
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value		206,002
Investment Securities, Portfolio Concentration Not Rated, Fair Value		208,981
Fixed maturity securities [Member]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Carrying Value		99,628
Investment Securities, Debt Maturities, One to Five Years, Carrying Value		223,400
Investment Securities, Debt Maturities, Six to Ten Years, Carrying Value		133,229
Investment Securities, Debt Maturities, Over Ten Years, Carrying Value		69,111
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Carrying Value		525,368
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Fair Value		99,651
Investment Securities, Debt Maturities, One to Five Years, Fair Value		225,365
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		147,846
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		71,158
Investment Securities, Debt Maturities, Single Maturity Date, Fair value		$ 544,020
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield		1.77%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield		2.65%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield		5.75%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield		5.08%
Investment Securities, Debt Maturities, Nominal Yield		3.59%
Investment Securities, Debt Maturities, Weighted Average Maturity	[3]	4.68
Municipal and other tax-exempt securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		$ 320,364		365,258
Investment Securities, Debt Maturities, Carrying Value		320,364		365,258
Investment Securities, Fair Value		321,225		368,910
Investment Securities, Gross Unrealized Gain		2,272	[1]	3,935	[2]
Investment Securities, Gross Unrealized Loss		(1,411)	[1]	(283)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Carrying Value		83,583
Investment Securities, Debt Maturities, One to Five Years, Carrying Value		181,596
Investment Securities, Debt Maturities, Six to Ten Years, Carrying Value		5,909
Investment Securities, Debt Maturities, Over Ten Years, Carrying Value		49,276
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Carrying Value		320,364
Investment Securities, Debt Maturities, Carrying Value		320,364		365,258
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Fair Value		83,544
Investment Securities, Debt Maturities, One to Five Years, Fair Value		180,993
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		5,836
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		50,852
Investment Securities, Debt Maturities, Single Maturity Date, Fair value		321,225
Investment Securities, Fair Value		$ 321,225		$ 368,910
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield	[4]	1.48%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield	[4]	2.08%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield	[4]	3.31%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield	[4]	5.20%
Investment Securities, Debt Maturities, Nominal Yield	[4]	2.43%
Investment Securities, Debt Maturities, Weighted Average Maturity	[3]	3.41
Investment Securities, Debt Maturities, Effective tax rate for nominal yield calculation		39.00%
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		151		73
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 219,892		$ 127,319
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		4,333		13,380
Investment Securities, Continuous Unrealized Loss Position, Fair Value		224,225		140,699
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		1,316		206
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		95		77
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		1,411		283
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value		193,931
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value		193,834
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value		6,028
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value		6,037
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value		120,405
Investment Securities, Portfolio Concentration Not Rated, Fair Value		121,354
Other debt securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		205,004		205,745
Investment Securities, Debt Maturities, Carrying Value		205,004		205,745
Investment Securities, Fair Value		222,795		232,375
Investment Securities, Gross Unrealized Gain		18,115	[1]	26,689	[2]
Investment Securities, Gross Unrealized Loss		(324)	[1]	(59)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Carrying Value		16,045
Investment Securities, Debt Maturities, One to Five Years, Carrying Value		41,804
Investment Securities, Debt Maturities, Six to Ten Years, Carrying Value		127,320
Investment Securities, Debt Maturities, Over Ten Years, Carrying Value		19,835
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Carrying Value		205,004
Investment Securities, Debt Maturities, Carrying Value		205,004		205,745
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Fair Value		16,107
Investment Securities, Debt Maturities, One to Five Years, Fair Value		44,372
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		142,010
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		20,306
Investment Securities, Debt Maturities, Single Maturity Date, Fair value		222,795
Investment Securities, Fair Value		$ 222,795		$ 232,375
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Nominal Yield		3.28%
Investment Securities, Debt Maturities, One to Five Years, Nominal Yield		5.14%
Investment Securities, Debt Maturities, Six to Ten Years, Nominal Yield		5.86%
Investment Securities, Debt Maturities, Over Ten Years, Nominal Yield		4.79%
Investment Securities, Debt Maturities, Nominal Yield		5.41%
Investment Securities, Debt Maturities, Weighted Average Maturity	[3]	6.66
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		41		11
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 11,820		$ 1,082
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		855		1,715
Investment Securities, Continuous Unrealized Loss Position, Fair Value		12,675		2,797
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		322		41
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		2		18
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		324		59
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value		140,184
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value		156,641
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value		0
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value		0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value		64,820
Investment Securities, Portfolio Concentration Not Rated, Fair Value		66,154
U.S. government agency residential mortgage-backed securities [Member] | Other [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Amortized Cost		20,777		26,721
Investment Securities, Debt Maturities, Carrying Value		20,777	[5]	26,833
Investment Securities, Fair Value		21,473	[5]	27,874
Investment Securities, Gross Unrealized Gain		767	[1]	1,063	[2]
Investment Securities, Gross Unrealized Loss		(71)	[1]	(22)	[2]
Investment Securities, Debt Maturities, Carrying Value [Abstract]
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Carrying value		20,777
Investment Securities, Debt Maturities, Carrying Value		20,777	[5]	26,833
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, without Single Maturity Date, Fair value		21,473
Investment Securities, Fair Value		$ 21,473	[5]	$ 27,874
Investment Securities, Debt Maturities, Nominal Yield [Abstract]
Investment Securities, Debt Maturities, Nominal Yield	[6]	2.76%
Investment Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities		4 years 8 months 12 days
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		1		1
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 4,358		$ 5,533
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value		4,358		5,533
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses		71		22
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		0		0
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		71		$ 22
Other than Temporary Impairment Losses, Investment Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Investment Securities, Portfolio Concentration Rated AAA to AA, Carrying Value	[5]	0
Investment Securities, Portfolio Concentration Rated AAA to AA, Fair Value	[5]	0
Investment Securities, Portfolio Concentration Rated A to BBB, Carrying Value	[5]	0
Investment Securities, Portfolio Concentration Rated A to BBB, Fair Value	[5]	0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Carrying Value	[5]	0
Investment Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	[5]	0
Investment Securities, Portfolio Concentration Not Rated, Carrying Value	[5]	20,777
Investment Securities, Portfolio Concentration Not Rated, Fair Value	[5]	$ 21,473

[1] Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.

[2] Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.

[3] Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty.

[4] Calculated on a taxable equivalent basis using a 39% effective tax rate.

[5] U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.

[6] The nominal yield on residential mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary - Unaudited for current yields on the investment securities portfolio.