Securities (Securities in a Continuous Unrealized Loss Position) (Details) $ in Thousands	Dec. 31, 2016 USD ($) security	Dec. 31, 2015 USD ($) security
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	47	16
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 505,906	$ 97,766
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (12,726)	$ (858)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	10	10
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 26,736	$ 25,138
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ (3,115)	$ (4,677)
Number of individual name issuer trust preferred securities in a continuous unrealized loss position total | security	57	26
Fair value of securities in a continuous unrealized loss position total	$ 532,642	$ 122,904
Unrealized losses of securities in a continuous unrealized loss position total	$ (15,841)	$ (5,535)
Obligations of U.S. government agencies and U.S. government-sponsored enterprises [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	10	4
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 98,433	$ 34,767
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (3,050)	$ (388)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	0	0
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 0	$ 0
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ 0	$ 0
Number of individual name issuer trust preferred securities in a continuous unrealized loss position total | security	10	4
Fair value of securities in a continuous unrealized loss position total	$ 98,433	$ 34,767
Unrealized losses of securities in a continuous unrealized loss position total	$ (3,050)	$ (388)
Mortgage-backed securities issued by U.S. government-sponsored agencies and U.S. government-sponsored enterprises [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	35	9
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 407,073	$ 61,764
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (9,671)	$ (450)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	0	0
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 0	$ 0
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ 0	$ 0
Number of individual name issuer trust preferred securities in a continuous unrealized loss position total | security	35	9
Fair value of securities in a continuous unrealized loss position total	$ 407,073	$ 61,764
Unrealized losses of securities in a continuous unrealized loss position total	$ (9,671)	$ (450)
Individual name issuer trust preferred debt securities [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	0	0
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 0	$ 0
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ 0	$ 0
Number of securities in a continuous unrealized loss position for 12 months or longer | security	10	10
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 26,736	$ 25,138
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ (3,115)	$ (4,677)
Number of individual name issuer trust preferred securities in a continuous unrealized loss position total | security	10	10
Fair value of securities in a continuous unrealized loss position total	$ 26,736	$ 25,138
Unrealized losses of securities in a continuous unrealized loss position total	$ (3,115)	$ (4,677)
Corporate bonds [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Number of securities in a continuous unrealized loss position for less than 12 months | security	2	3
Fair value of securities in a continuous unrealized loss position for less than 12 months	$ 400	$ 1,235
Unrealized losses of securities in a continuous unrealized loss position for less than 12 months	$ (5)	$ (20)
Number of securities in a continuous unrealized loss position for 12 months or longer | security	0	0
Fair value of securities in a continuous unrealized loss position for 12 months or longer	$ 0	$ 0
Unrealized losses of securities in a continuous unrealized loss position for 12 months or longer	$ 0	$ 0
Number of individual name issuer trust preferred securities in a continuous unrealized loss position total | security	2	3
Fair value of securities in a continuous unrealized loss position total	$ 400	$ 1,235
Unrealized losses of securities in a continuous unrealized loss position total	$ (5)	$ (20)