CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Unrealized holding gain arising during the period, tax expense	$ 375,000,000	$ 1,700,000
Reclassification adjustment for net losses included in net income, tax benefit (expense)	67,000	(6,000)
Unrealized loss on derivative instruments designated as cash flow hedges, tax expense (benefit)	$ (137,000)	$ (82,000)