Securities (Summary of Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Available for sale securities amortized cost	$ 750,745	$ 373,376
Available for sale securities unrealized gains	5,008	7,203
Available for sale securities unrealized losses	(15,841)	(5,535)
Available for sale, at fair value	739,912	375,044
Held to maturity securities amortized cost	15,633	20,023
Held to maturity securities unrealized gains	287	493
Held to Matruity securities unrealized losses	0	0
Held to maturity securities fair value	15,920	20,516
Total securities amortized cost	766,378	393,399
Total securities unrealized gains	5,295	7,696
Total securities unrealized losses	(15,841)	(5,535)
Total securities fair value	755,832	395,560
Available for sale securities amortized cost	750,745
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]
Available for sale securities amortized cost	111,483	77,330
Available for sale securities unrealized gains	7	73
Available for sale securities unrealized losses	(3,050)	(388)
Available for sale, at fair value	108,440	77,015
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]
Available for sale securities amortized cost	592,833	228,908
Available for sale securities unrealized gains	4,923	6,398
Available for sale securities unrealized losses	(9,671)	(450)
Available for sale, at fair value	588,085	234,856
Held to maturity securities amortized cost	15,633	20,023
Held to maturity securities unrealized gains	287	493
Held to Matruity securities unrealized losses	0	0
Held to maturity securities fair value	15,920	20,516
Obligations of states and political subdivisions [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Available for sale securities amortized cost	14,423	35,353
Available for sale securities unrealized gains	62	727
Available for sale securities unrealized losses	0	0
Available for sale, at fair value	14,485	36,080
Individual name issuer trust preferred debt securities [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Available for sale securities amortized cost	29,851	29,815
Available for sale securities unrealized gains	0	0
Available for sale securities unrealized losses	(3,115)	(4,677)
Available for sale, at fair value	26,736	25,138
Corporate bonds [Member]
Schedule of Available for Sale and Held to Maturity Securities [Line Items]
Available for sale securities amortized cost	2,155	1,970
Available for sale securities unrealized gains	16	5
Available for sale securities unrealized losses	(5)	(20)
Available for sale, at fair value	$ 2,166	$ 1,955

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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