Investment Securities (Narrative) (Details) |
3 Months Ended | 12 Months Ended | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2015
USD ($)
securities
|
Sep. 30, 2015
USD ($)
|
Jun. 30, 2015
USD ($)
|
Mar. 31, 2015
USD ($)
|
Dec. 31, 2014
USD ($)
|
Sep. 30, 2014
USD ($)
|
Jun. 30, 2014
USD ($)
|
Mar. 31, 2014
USD ($)
|
Dec. 31, 2015
USD ($)
securities
|
Dec. 31, 2014
USD ($)
|
Dec. 31, 2013
USD ($)
|
|
Schedule of Available-for-sale Securities [Line Items] | |||||||||||
Transfer of available-for-sale securities to held-to-maturity securities | $ 862,712,000 | $ 0 | $ 0 | ||||||||
Available-for-sale securities, transferred to held-to-maturity, unrealized gain(loss) | 14,400,000 | ||||||||||
Income tax expense | $ 20,896,000 | $ 23,842,000 | $ 26,295,000 | $ 23,983,000 | $ 23,669,000 | $ 25,034,000 | $ 24,490,000 | $ 21,840,000 | 95,016,000 | 95,033,000 | 87,230,000 |
Investment securities pledged as collateral | $ 1,200,000,000 | $ 1,100,000,000 | $ 1,200,000,000 | 1,100,000,000 | |||||||
Number of securities by a single non-goverment sponsored issuer exceeding 10% of shareholders' equity | securities | 0 | 0 | |||||||||
Available-for-sale securities | |||||||||||
Schedule of Available-for-sale Securities [Line Items] | |||||||||||
Income tax expense | $ 122,000 | $ 194,000 | $ 1,200,000 |