Earnings Per Common Share (Schedule of Basic and Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Earnings Per Share [Abstract]
Net income (loss)	$ 19,973		$ 13,276		$ 14,591		$ 12,176		$ 13,462		$ 11,880		$ 11,899		$ 8,902		$ 60,016		$ 46,143		$ 48,037
Earnings allocated to participating securities - preferred shares																	95		0		0
Earnings allocated to participating securities - nonvested restricted shares																	523		443		450
Weighted average common shares outstanding																	47,993		39,260		39,103
Earnings (loss) basic (dollars per share)	$ 0.39	[1]	$ 0.26	[1]	$ 0.28	[1]	$ 0.31	[1]	$ 0.34	[1]	$ 0.30	[1]	$ 0.30	[1]	$ 0.22	[1]	$ 1.24	[1]	$ 1.16	[1]	$ 1.22
Earnings allocated to common shareholders, Diluted																	$ 59,407		$ 45,700		$ 47,588
Weighted average number of common shares outstanding																	47,993		39,260		39,103
Dilutive effect of equity awards and warrants																	1,058		3		77
Weighted average diluted common shares outstanding																	49,051		39,263		39,180
Earnings (loss) diluted (dollars per share)	$ 0.38	[1]	$ 0.25	[1]	$ 0.28	[1]	$ 0.31	[1]	$ 0.34	[1]	$ 0.30	[1]	$ 0.30	[1]	$ 0.22	[1]	$ 1.21	[1]	$ 1.16	[1]	$ 1.21
Potentially dilutive share options that were not included in the computation of diluted EPS because to do so would be anti-dilutive.																	64		9		53

[1] Due to averaging of shares, quarterly earnings per share may not add up to the totals reported for the full year.